How to add and edit MIDI events

Hello, I am a potential new user assessing the n-Track iOS trial version on iPadPro. I will be using n-track to play MIDI drum tracks through my Alesis SR18 drum machine and send MIDI events, PCs specifically but also CCs, to my GigRig G2 based guitar pedal board.

N-track appears to be exactly what I have been looking for with one exception, for the life of me I can not work out how to add the PCs and CCs to the piano roll!
I am sure it is glaringly obvious but searching through the user guide, forum and Google have so far not provided an answer. Can one of you knowledgeable folk please help me?