1. adjust the record gain
2. press record
and then i assume you'll find a way to press stop ... press the down arrow to the ASSIGN PAD line .. then turn the data wheel to A1 ( that you previously set to the right volume/tune/attack/decay etc.... ) then press keep ... then go to the main window... press record/play.... record a sequence with LOOP ON ... all this in a short amount of time
if you can do that in 4-5 seconds in a breakdown or something you're an MPC half-god.