diff --git a/src/main/java/de/studiocode/invui/gui/GUI.java b/src/main/java/de/studiocode/invui/gui/GUI.java
index 24375d8..7fbec12 100644
--- a/src/main/java/de/studiocode/invui/gui/GUI.java
+++ b/src/main/java/de/studiocode/invui/gui/GUI.java
@@ -2,6 +2,9 @@ package de.studiocode.invui.gui;
 
 import de.studiocode.invui.animation.Animation;
 import de.studiocode.invui.gui.SlotElement.ItemStackHolder;
+import de.studiocode.invui.gui.builder.GUIBuilder;
+import de.studiocode.invui.gui.builder.PagedGUIBuilder;
+import de.studiocode.invui.gui.builder.TabGUIBuilder;
 import de.studiocode.invui.gui.impl.*;
 import de.studiocode.invui.item.Item;
 import de.studiocode.invui.virtualinventory.VirtualInventory;
@@ -32,7 +35,11 @@ import java.util.function.Predicate;
  * @see PagedGUI
  * @see SimpleGUI
  * @see SimplePagedItemsGUI
- * @see SimplePagedGUIs
+ * @see SimplePagedGUIsGUI
+ * @see SimpleTabGUI
+ * @see GUIBuilder
+ * @see PagedGUIBuilder
+ * @see TabGUIBuilder
  */
 public interface GUI extends GUIParent {
     
diff --git a/src/main/java/de/studiocode/invui/gui/builder/PagedGUIBuilder.java b/src/main/java/de/studiocode/invui/gui/builder/PagedGUIBuilder.java
index 60cf52f..5b81a56 100644
--- a/src/main/java/de/studiocode/invui/gui/builder/PagedGUIBuilder.java
+++ b/src/main/java/de/studiocode/invui/gui/builder/PagedGUIBuilder.java
@@ -3,7 +3,7 @@ package de.studiocode.invui.gui.builder;
 import de.studiocode.invui.gui.GUI;
 import de.studiocode.invui.gui.SlotElement;
 import de.studiocode.invui.gui.impl.PagedGUI;
-import de.studiocode.invui.gui.impl.SimplePagedGUIs;
+import de.studiocode.invui.gui.impl.SimplePagedGUIsGUI;
 import de.studiocode.invui.gui.impl.SimplePagedItemsGUI;
 import de.studiocode.invui.item.Item;
 import de.studiocode.invui.item.itembuilder.ItemBuilder;
@@ -45,7 +45,7 @@ public class PagedGUIBuilder extends GUIBuilder {
         
         PagedGUI gui;
         if (contentType == ContentType.GUI) {
-            gui = new SimplePagedGUIs(width, height, backSlot, backFunction,
+            gui = new SimplePagedGUIsGUI(width, height, backSlot, backFunction,
                 forwardSlot, forwardFunction, (List<GUI>) content, listSlots);
         } else {
             gui = new SimplePagedItemsGUI(width, height, backSlot, backFunction,
diff --git a/src/main/java/de/studiocode/invui/gui/impl/PagedGUI.java b/src/main/java/de/studiocode/invui/gui/impl/PagedGUI.java
index b0d5082..8f3aa72 100644
--- a/src/main/java/de/studiocode/invui/gui/impl/PagedGUI.java
+++ b/src/main/java/de/studiocode/invui/gui/impl/PagedGUI.java
@@ -1,12 +1,21 @@
 package de.studiocode.invui.gui.impl;
 
+import de.studiocode.invui.gui.GUI;
 import de.studiocode.invui.gui.SlotElement;
+import de.studiocode.invui.gui.builder.PagedGUIBuilder;
 import de.studiocode.invui.item.Item;
 import de.studiocode.invui.item.impl.pagedgui.BackItem;
 import de.studiocode.invui.item.impl.pagedgui.ForwardItem;
 
 import java.util.List;
 
+/**
+ * A {@link GUI} with pages.
+ *
+ * @see PagedGUIBuilder
+ * @see SimplePagedItemsGUI
+ * @see SimplePagedGUIsGUI
+ */
 public abstract class PagedGUI extends BaseGUI {
     
     private final boolean infinitePages;
@@ -49,6 +58,7 @@ public abstract class PagedGUI extends BaseGUI {
     }
     
     protected void update() {
+        correctPage();
         updateControlItems();
         updatePageContent();
     }
@@ -58,19 +68,20 @@ public abstract class PagedGUI extends BaseGUI {
         forwardItem.notifyWindows();
     }
     
-    private void updatePageContent() {
-        if (getCurrentPageIndex() < getPageAmount()) {
-            List<SlotElement> slotElements = getPageItems(currentPage);
-            
-            for (int i = 0; i < itemListSlots.length; i++) {
-                if (slotElements.size() > i) setSlotElement(itemListSlots[i], slotElements.get(i));
-                else remove(itemListSlots[i]);
-            }
-        } else setCurrentPage(getPageAmount() - 1);
+    private void correctPage() {
+        if (currentPage == 0) return;
+        int pageAmount = getPageAmount();
+        if (currentPage < 0) currentPage = 0;
+        else if (currentPage >= pageAmount) currentPage = pageAmount - 1;
     }
     
-    public int getCurrentPageIndex() {
-        return currentPage;
+    private void updatePageContent() {
+        List<SlotElement> slotElements = getPageElements(currentPage);
+        
+        for (int i = 0; i < itemListSlots.length; i++) {
+            if (slotElements.size() > i) setSlotElement(itemListSlots[i], slotElements.get(i));
+            else remove(itemListSlots[i]);
+        }
     }
     
     private void setCurrentPage(int page) {
@@ -96,6 +107,6 @@ public abstract class PagedGUI extends BaseGUI {
     
     public abstract int getPageAmount();
     
-    protected abstract List<SlotElement> getPageItems(int page);
+    protected abstract List<SlotElement> getPageElements(int page);
     
 }
diff --git a/src/main/java/de/studiocode/invui/gui/impl/SimpleGUI.java b/src/main/java/de/studiocode/invui/gui/impl/SimpleGUI.java
index 6c2743d..28a348b 100644
--- a/src/main/java/de/studiocode/invui/gui/impl/SimpleGUI.java
+++ b/src/main/java/de/studiocode/invui/gui/impl/SimpleGUI.java
@@ -1,5 +1,10 @@
 package de.studiocode.invui.gui.impl;
 
+import de.studiocode.invui.gui.GUI;
+
+/**
+ * A normal {@link GUI} without any special features.
+ */
 public class SimpleGUI extends BaseGUI {
     
     public SimpleGUI(int width, int height) {
diff --git a/src/main/java/de/studiocode/invui/gui/impl/SimplePagedGUIs.java b/src/main/java/de/studiocode/invui/gui/impl/SimplePagedGUIsGUI.java
similarity index 53%
rename from src/main/java/de/studiocode/invui/gui/impl/SimplePagedGUIs.java
rename to src/main/java/de/studiocode/invui/gui/impl/SimplePagedGUIsGUI.java
index 085a655..7b73614 100644
--- a/src/main/java/de/studiocode/invui/gui/impl/SimplePagedGUIs.java
+++ b/src/main/java/de/studiocode/invui/gui/impl/SimplePagedGUIsGUI.java
@@ -2,6 +2,7 @@ package de.studiocode.invui.gui.impl;
 
 import de.studiocode.invui.gui.GUI;
 import de.studiocode.invui.gui.SlotElement;
+import de.studiocode.invui.gui.builder.PagedGUIBuilder;
 import de.studiocode.invui.item.impl.pagedgui.BackItem;
 import de.studiocode.invui.item.impl.pagedgui.ForwardItem;
 import de.studiocode.invui.item.itembuilder.ItemBuilder;
@@ -10,14 +11,20 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.function.Function;
 
-public class SimplePagedGUIs extends PagedGUI {
+/**
+ * A {@link PagedGUI} where every page is it's own {@link GUI}.
+ * 
+ * @see PagedGUIBuilder
+ * @see SimplePagedItemsGUI
+ */
+public class SimplePagedGUIsGUI extends PagedGUI {
     
-    private final List<GUI> guis;
+    private List<GUI> guis;
     
-    public SimplePagedGUIs(int width, int height,
-                           int backItemSlot, Function<PagedGUI, ItemBuilder> backFunction,
-                           int forwardItemSlot, Function<PagedGUI, ItemBuilder> forwardFunction,
-                           List<GUI> guis, int... itemListSlots) {
+    public SimplePagedGUIsGUI(int width, int height,
+                              int backItemSlot, Function<PagedGUI, ItemBuilder> backFunction,
+                              int forwardItemSlot, Function<PagedGUI, ItemBuilder> forwardFunction,
+                              List<GUI> guis, int... itemListSlots) {
         
         super(width, height, false, itemListSlots);
         this.guis = guis;
@@ -34,8 +41,13 @@ public class SimplePagedGUIs extends PagedGUI {
     }
     
     @Override
-    protected List<SlotElement> getPageItems(int page) {
+    protected List<SlotElement> getPageElements(int page) {
         return Arrays.asList(guis.get(page).getSlotElements());
     }
     
+    public void setGuis(List<GUI> guis) {
+        this.guis = guis;
+        update();
+    }
+    
 }
diff --git a/src/main/java/de/studiocode/invui/gui/impl/SimplePagedItemsGUI.java b/src/main/java/de/studiocode/invui/gui/impl/SimplePagedItemsGUI.java
index 51d6a64..910e0c4 100644
--- a/src/main/java/de/studiocode/invui/gui/impl/SimplePagedItemsGUI.java
+++ b/src/main/java/de/studiocode/invui/gui/impl/SimplePagedItemsGUI.java
@@ -2,6 +2,7 @@ package de.studiocode.invui.gui.impl;
 
 import de.studiocode.invui.gui.SlotElement;
 import de.studiocode.invui.gui.SlotElement.ItemSlotElement;
+import de.studiocode.invui.gui.builder.PagedGUIBuilder;
 import de.studiocode.invui.item.Item;
 import de.studiocode.invui.item.impl.pagedgui.BackItem;
 import de.studiocode.invui.item.impl.pagedgui.ForwardItem;
@@ -11,9 +12,15 @@ import java.util.List;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+/**
+ * A {@link PagedGUI} that is filled with {@link Item}s.
+ * 
+ * @see PagedGUIBuilder
+ * @see SimplePagedGUIsGUI
+ */
 public class SimplePagedItemsGUI extends PagedGUI {
     
-    private final List<Item> items;
+    private List<Item> items;
     
     public SimplePagedItemsGUI(int width, int height,
                                int backItemSlot, Function<PagedGUI, ItemBuilder> backFunction,
@@ -34,7 +41,7 @@ public class SimplePagedItemsGUI extends PagedGUI {
     }
     
     @Override
-    protected List<SlotElement> getPageItems(int page) {
+    protected List<SlotElement> getPageElements(int page) {
         int length = getItemListSlots().length;
         int from = page * length;
         int to = Math.min(from + length, items.size());
@@ -42,4 +49,8 @@ public class SimplePagedItemsGUI extends PagedGUI {
         return items.subList(from, to).stream().map(ItemSlotElement::new).collect(Collectors.toList());
     }
     
+    public void setItems(List<Item> items) {
+        this.items = items;
+        update();
+    }
 }
diff --git a/src/main/java/de/studiocode/invui/gui/impl/SimpleTabGUI.java b/src/main/java/de/studiocode/invui/gui/impl/SimpleTabGUI.java
index 3af5797..a69198d 100644
--- a/src/main/java/de/studiocode/invui/gui/impl/SimpleTabGUI.java
+++ b/src/main/java/de/studiocode/invui/gui/impl/SimpleTabGUI.java
@@ -2,6 +2,7 @@ package de.studiocode.invui.gui.impl;
 
 import de.studiocode.invui.gui.GUI;
 import de.studiocode.invui.gui.SlotElement;
+import de.studiocode.invui.gui.builder.TabGUIBuilder;
 import de.studiocode.invui.item.impl.tabgui.TabItem;
 import de.studiocode.invui.item.itembuilder.ItemBuilder;
 
@@ -11,6 +12,11 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.function.Function;
 
+/**
+ * A {@link GUI} that has multiple tabs with which users can switch between {@link GUI}s.
+ * 
+ * @see TabGUIBuilder
+ */
 public class SimpleTabGUI extends TabGUI {
     
     private final List<GUI> tabs;