how to do it correctly, any advice pleasee?

You want to chop on the start and end of a beat or a measure. In most modern music the rhythm is layed down in a 4/4 pattern. This means that one measure or bar of a song is comprised of 4 beats, so Kick>snare>kick>snare would be a full bar in like a standard rock song or whatever, you see that together there are 2 kicks and 2 snares that occur in that bar, each one is one beat or a 1/4 note. The rhythm is designed like this to be interlocking and expandable by multiples of 4. Since all modern music has a 4/4 time(Jazz is mostly 4/4 but also a lot of off time sigs like Time Out by Dave Brubeck) you can mix and match songs because they are based on the same rhythmic timing but different tempos, which ends up not mattering in hip hop too much as long as you put the sample on beat.

ooooh sorry for askign all these questions...dood thx alot...that tottaly helped me out....wow you are a genious...mad props man