Help modifying UI (calling event handlers)

Trying to get my head around the event handlers for the UI and I just can’t quite figure it out. I’m sure this way is great from a code optimisation point of view, but hard to follow.

Maybe someone can just gimme a shortcut here…

How would I call OnIncrement directly parameter 24 (PRM_UI_ACTIVE_ENV_LFO) ??

I’m trying to add a function to cycle through the ENV and MOD pages if the corresponding switch is pressed repeatedly.