No don't compile anything. Get Easy Debian, then when you've got it all set up, use Synaptic (the icon is installed with Easy Debian) or "apt-get install mumble" (from the Debian Chroot prompt) to install Mumble. If you want to run mumble, you'll want to run it as user, not as root, so, once it is installed, open a new terminal and type "debbie mumble" and see what happens...