I havent touched my volca modular in two years and even back then did not dig deep. I suggest to look at many videos of the volca modular, there is one input you need a cable with a stereo plug to two monos so you have two inputs, on the volca there are patchpoints from which you can patch each of those two inputs to the destination of your choice. As far as i rememember its definitely possible to clock the sequencer.
Maybe you want to look into "undulations" youtubes channel he has in depth videos about the volca modular that might cover that.
I should dig out mine sometimes.
...edit and yes a gate is not a gate and a trig is not a trig, there are different formats, i don't know what the keystep puts out.