There is just one rule :
Per track you can’t play more than one sample at the same time.
Besides this simple rule, you can sequence all the samples you want on the same track. You can have samples from different slots, slides, etc
For example if you have a sliced drum loop sequenced on a track, and then you want to change the Snare for a clap that you have on other sample slot on the pool, of course you can, also you can change that snare by another snare from another sliced drum loop that you have in another sample slot.
Try the sample lock function.
Wile step recording, press and hold a Trigger, then move the Level knob, you’ll see a list with all the sample you have on the pool for that particular machine, either static or flex.