Yo, that's the other part I was talking about. Go to trim mode and extract the sample to another pad. This makes two different samples that are the same sound. Chop one and leave the other alone, extract again, repeat. This is how you chop a riff. For example: the whole melody is on one sample, extract it 7 times to get 8 of the same sample - then trim each one to give you 8 different starting places from the riff (chopping a 4/4 piece into 8 pieces or however you want to do it), then you can rearrange that riff that you chopped.