changed README.md

README.md

 **Getting started**
 
-1. Run main file to start main server
-2. run client register to add sub server or register to existing server
+1. Run `start_server.py` file to start a server. If there is no existing Server in the DS the server will declare himsel as new `MAIN`
+2. Run `start_server.py` a second time to add a new server to the DS. The `MAIN` server will answer the new server and assign him a group.
+3. Run `client_register.py` to start a client an register him to a group.