I personally don't think the repetition tool is *that* hard to grok, and it's not because I'm smarter than anyone else!
Last time I explained it, Evan accused me of being a lousy writer, but hopefully this time he'll SHUT THE HECK UP if he still has that opinion. Or even if he doesn't, because I'm not in the mood to be insulted. [:)]
Okay. They record an instrument playing, say, c-c-c-c-c-c-c at a given tempo.
That repeated-note performance is chopped up into programs that start playback at the beginning of each note in the performance. Each time you play a note, a keyswitch is sent to change to another program, i.e. to start with another note from the performance.
The main reason the performance is chopped up, of course, is so you can play at your tempo rather than the recorded one. That works fine if you play at or (up to a point) faster than the recorded tempo, but the performance will get ahead of you - the next recorded note will sound - if you play slower. (The length of the notes determines the limit to how fast you can play, i.e. it will sound wrong if they overlap.)
You can specify whether a note in the performance is played or skipped by using the 1 0 1 0 stuff (1=play it, 0=skip it), you can loop that 1 0 1 0 pattern if you need more than the number of repetitions in it, and you can string together different patterns if you want a variation.