Yes, you can play with just drums. The easiest way to do this is to mute the other instruments.

To mute all instruments except the drums, double click on the "Drums" Radio button at the top, and use the menu and choose "Solo"

Then, for the rest of the session, you will hear only drums, regardless of what song is being played.

If your songs are of unknown length, and you want drums to be playing all the time (without a count-in, and ending bars), then you should turn off the count-in (Preferences), and make sure that overall loop is set for the song. That way it will endlessly loop.

Have Fun!
Peter Gannon
PG Music Inc.