How to set up PRmumble

[Poker9]

I have a Realtek HD headphones and mic but im a little confused on PRmumble? Do i start PRmumble in game or before i play the game? Do i leave it running and if you do leave it running the talk button "B" isnt working?? How do i set up my mic?

[Jutsch]

Mumble starts automatically when you start the game.
You can adjust the in and output of mumble in the sound settings.
Press H for local voice, 0 on the numpad for squadchat, and if you are commander or quadleader, use the numbers on the numpad to call the other officers.