See this thread - all kinds of preferred methods to change states.
Essentially, you can
- use a foot pedal to advance to the next state - good if you play sitting down, so you have two feet to play with
- use a button or a pad on your keyboard - it is essential that you can reach it easily while playing but don’t hit it accidentally
You now create a binding from your preferred pedal or button using either “Controller (Button)” or “Note” (in the case of drum pads) to “SongStates / Next State (Instant)”, and things should work out nicely.
If you want to use drum pads, you’ll need to make sure they send on a different MIDI channel than your keys and then specify that MIDI channel in your binding, so your “next state” isn’t triggered by your playing on the keyboard…
Since I play standing up, a pedal is not convenient to me (I usually have my right foot in use for sustain or expression, so I need my left to stand on 
). I mostly use my “big red button” that is plugged into one of the switch pedal ports of my master keyboard:
Alternatively, I use one of the drum pads of my upper keyboard - I am using the bottom row of pads to control LivePrompter and Cantabile’s next state.
I also have some buttons on my upper keyboard assigned to control Cantabile states, but these are too fiddly to use in anger during a gig, so they are mainly for navigating during rehearsals or between songs:
Cheers,
Torsten