Added some API notes

README.md

@@ -3,6 +3,57 @@ libtun
 
 TUN/TAP adapter for D-based applications
 
+## Usage
+
+First add it to your dub-based project via:
+
+```
+dub add libtun
+```
+
+### `TUNAdapter`
+
+The `TUNAdapter` class provides you with all you need to get started. One can construct a new adapter as follows:
+
+```d
+import libtun.adapter;
+
+void main()
+{
+    try
+    {
+        TUNAdapter tun = new TUNAdapter("interface0", AdapterType.TUN);
+    }
+    catch(TUNException)
+    {
+
+    }
+}
+```
+
+Reading and writing is easy:
+
+```d
+byte[] data;
+
+try
+{
+    tun.receive(data);
+    tun.write([65,66,66,65]);
+}
+catch(TUNException)
+{
+
+}
+```
+
+There are two types of adapters:
+
+1. `AdapterType.TUN`
+    * This is for creating a TUN device
+2. `AdapterType.TAP`
+    * This is for creating a TAP device
+
 ## License
 
 LGPLv3