i'm gonna suggest something even more boring than peterpiper and suggest this site:
http://www.drumlessons.com/its a great site with video demos and practice tracks as well, you just need to adapt it to the mpc.
but for the mpc before you even load up any samples you need to figure out what it is you want to do,...
do you want to play it like a drummer only? ie two hands for drums alone?
this isnt that complicated,...
for the right handed,.... you play hh and kick with your right, with the hh finger leading, and snare with your left, more or less as you would with a regular kit. i've found that the index finger on hh and middle on kick to be the easiest combination. for this i'd load the bottom row with:
snare-hh-kick-2nd kick
and the row above that with varitions or and open hh, etc, whatever you fancy.
and the round robin thing is brilliant for this.
if you're looking to trigger musical samples i've found the above technique somewhat lacking,... or i'm just not fast enough. so i wind up playing and setting up differently:
snare1 - kick - hh - snare2
this lets me play kick, hh and snare2 with my right hand, index, middle, ring/pinky respectively, freeing up my left hand for snare1 and triggering the musical samples on the top two rows of pads.
so snare rolls are comfortably two handed, and row two will have variations on the bottom row samples, or if the song calls for it toms, etc.
this is a bit trickier as i 've found my ring finger to be stupidly weak, hitting the snare in time with the hh sometimes. its a **** to get right but with practice you'll get it.
i hope that helps some.
but as the others have said,... there's no right or wrong way, just efficient and inefficient, and everyone's definition of that is different. with practice you not only learn to play, but you figure out what feels natural to you and you move the pads accordingly. for example i had snares grouped together at one time, but found rolls to be too cramped so now they're on opposite ends, which for me better mimics the actions of a roll,... on the other hand someone else might find placing them right next to each other easier to focus on.
disclaimer: i've only been doing this for a short while, so i might wind up changing my mind completely next week
