First of all you need to turn of the caps lock on your keyboard looks like you're shouting

. As for your sampling question. The sample you make has nothing to do with the tempo in the main screen. That tempo is just an indication of the speed with which the notes in your sequence are played. So let's say you sample a piano melody and you want to loop it then you do as follows; assign the sample to a pad set its mode to MONO (don't ask me how to do that it's all in the manual). Now go back to your main screen and press the rec key + the pad on which you assigned the piano sample. Now press play and you will hear your piano sample play. If you hear that the sample gets cut off to soon (aka u don't hear the whole sample then that means that the tempo set in main screen is too high) or too late (you hear a gap of silence after the sample played aka tempo set too low) then you need to adjust the tempo in the main screen until it sounds right. Also remember for this excersise the loop mode of your piano sample is TURNED OFF.
I hope this little explanation helps now go experiment and read the manual it is your friend. If all of this is too complicated or too hard to grasp then have a look @
www.mpc2000xl.net (great tutorials at a small fee) BUT DON'T COME BEGGING FOR PASSWORDS AROUND HERE OR YOU WILL BE BANNED FROM THE FORUM FOREVER (sorry 'bout the shouting but it seems there are a lot of cats out there who think everything comes for free.)