For clarity, lets say you are using Flash Media Live Encoder(FMLE) to publish a live stream to Wowza.
Assuming you followed the guide you linked to, when publishing a stream to Wowza from FMLE, you will be prompted for the username and password. Use the credentials that you entered while configuring your application for username and password.
The stream name is determined by what you name the stream in FLME, for instance when publishing a stream you enter a name in the "Stream" parameter, lets say "myStream"
You will also need to specify the application you are publishing to. So in FMLE it asks for the "FMS URL" This should look something like this " rtmp://[wowza-ip-address]:1935/live
Once the stream is published, you can test playback with the Wowza example RTMP player. The URL should look like this:
For playback in iOS player it would look like this
I hope this helps.