Okay. Is the keyboard connected to speakers? Do you have channel and patch (instrument sound) assignments in the MIDI track? You would probably want to use "General MIDI" for now.
Or, go to 'Insert' at the top and select Soft Synth>TTS-1 and set the MIDI track's output to TTS-1. Make sure you have chosen a channel and patch in the MIDI track.
Set the output of TTS-1 to your Behringer, or a bus that has it's output set to the Behringer.
On the mic and bass, you will want to select either L or R for their inputs since they are not stereo instruments.
I'm out. Bed time.
More info will follow tomorrow, I'm sure.
Some RTFM may be in order. ? It's not hard, so you should be going in no time.
Good luck!