In some aspects MDrummer is very different from any other drum VSTi, these are the powerful and genious aspects of MDrummer. On the other hand MDrummer is still compatible with the traditionel approach. If you have a GM drum track MIDI it will play on channel 10. Just import such a MIDI file to MDrummers MIDI track. And it will behave like an ordinary drum sampler. It will play exactly what is in your MIDI file. You could also use just a loop of say 4 bars of MIDI drums. And now you could copy this loop again and again into the MDIDI track. Boring. So import that MIDI loop into MDrummers base rhythm editor. From now on MDrummer is able to play "in the style" of this MIDI loop with many, many variations including fitting intros/outros/breaks! This approch can also be controlled by MIDI, but then use channel one. Verey note on channel 1 will be translated to a command by MDrummer. Open a MIDI item in Reaper and load the MDrummer key note text map. Now you will see that the MIDI keyboard within the editor has names like intro, outro, break, verse, chorus. So a note named intro on channel one will force MDrummer to play an intro! Or a break. If you take a low note called intro MDrummer will play less. If you take a higher note MDrummer will play more, more complicated and harder. No matter what, you will finally "render" or record the audio coming back from reaper on as many as 32 stereo tracks. These can also have additional FX within reaper like compressor or EQ.