ill help you out before you get BASHED by half the site telling you to use the search. sampling is taking somthing(drum hit,horn stab) from an already recorded source and using it to make your own music. when you chop your sample(im guessing you want to loop) you have to chop it so that it matches with the tempo of the song you are trying to create. tell me what equipment you are using and i can help you out more.