add basic usage instructions

README.md

@@ -1,2 +1,48 @@
 # wampproto-python
 Sans-IO implementation of the WAMP protocol in Python
+
+This is a library that could be used to build a [WAMP](https://wamp-proto.org/index.html) client or server. It operates
+on strings and bytes. A WAMP client can be split into two parts.
+
+* Session establishment
+* Session management.
+
+Assuming we have a websocket connection established to a WAMP server using sub protocol `wamp.2.json`. The first
+"message" is going to be sent by the client as HELLO
+```python
+from wampproto.joiner import Joiner
+
+j = Joiner("realm1")
+# this doesn't actually send the message, it just returns the
+# payload that needs to be sent over websocket.
+hello = j.send_hello()
+
+ws.send_str(hello)
+response = ws.receive_str()
+
+to_send = j.receive(response)
+if to_send is None:
+    # if there is nothing to send, this means
+    # the server returned WELCOME.
+    print(j.get_session_details())
+```
+
+Now that the session is established, we could instantiate a `WAMPSession` instance
+to handle further messages.
+```python
+from wampproto.session import WAMPSession
+from wampproto.messages import Call
+from wampproto.idgen import SessionScopeIDGenerator
+
+session = WAMPSession()
+idgen = SessionScopeIDGenerator()
+
+call = Call(idgen.next(), "foo.bar")
+to_send = session.send_message(call)
+
+ws.send_str(to_send)
+
+incoming_payload = ws.receive_str()
+result = session.receive(incoming_payload)
+print(result)
+```