diff --git a/docs/component/component.md b/docs/component/component.md
index 4d547a0..6e06737 100644
--- a/docs/component/component.md
+++ b/docs/component/component.md
@@ -1,4 +1,6 @@
+*[JavaECS](../../README.md) / [docs](../overview.md) / component*
 # Component
+
 ### Contents
 [About](#About)
 
diff --git a/docs/entity/entity.md b/docs/entity/entity.md
index 4580621..6c3f163 100644
--- a/docs/entity/entity.md
+++ b/docs/entity/entity.md
@@ -1,4 +1,6 @@
+*[JavaECS](../../README.md) / [docs](../overview.md) / entity*
 # Entity
+
 ### Contents
 [About](#About)
 
@@ -26,6 +28,9 @@ ___An entity contains no further data.___
 
 In order to be useful, its identifier must be registered to one or more [components](../component/component.md).
 
+
+Entities are also initialised with a Java [BitSet](). Each bit represents the index of a component, to determine which component an entity is registered to
+
 ## Usage
 *some specific usage info here*
 ``` java
@@ -35,3 +40,4 @@ void todo();
 ## Notes
 * The only requirement for a Entity is that it has a unique ID. An [entity manager](../manager/entity_manager.md) could implement a more complex ID system such as using a packed array for only a small region of IDs, or using named IDs by use of a dictionary or ordered hash-map
 * The maximum number of entities is limited by the size of the container used to store it. E.g., for a 32-bit unsigned integer, there are ~4.3 billion ID's available. But keep in mind that such a large amount of IDs will take significant time for each system to consider.
+* LinkedList is used to initialise the arrays, as a linked list is not limited to a maximum size: (https://stackoverflow.com/questions/3767979/how-much-data-can-a-list-can-hold-at-the-maximum)
diff --git a/docs/overview.md b/docs/overview.md
new file mode 100644
index 0000000..da644cb
--- /dev/null
+++ b/docs/overview.md
@@ -0,0 +1,16 @@
+*[JavaECS](../../README.md) / docs*
+# Entity
+### Contents
+[About](#About)
+
+[Usage](#Usage)
+
+[Notes](#Notes)
+
+### See also:
+[entity](./entity/entity.md)
+
+[component](./component/component.md)
+
+[system](./system/system.md)
+
diff --git a/docs/system/system.md b/docs/system/system.md
index 7ef9fe1..c5c6c56 100644
--- a/docs/system/system.md
+++ b/docs/system/system.md
@@ -1,7 +1,13 @@
+*[JavaECS](../../README.md) / [docs](../overview.md) / system*
 # System
+
 ### Contents
 [About](#About)
 
+[Implementation](#Implementation)
+
+[Examples](#Examples)
+
 ## About
 The system runs operations that must be performed on its assoiciated components.
 
@@ -20,5 +26,22 @@ void health_system(){
     }
 }
 ```
+## Implementation
+
+The systems are managed by the following code:
+
+``` java
+class SystemManager{
+    ECS baseECS;
+    int systemIndex;
+
+    public SystemManager(ECS baseECS){
+        this.baseECS = baseECS;
+        systemIndex = 0;
+    }
+}
+```
+
+## Examples