Depending on what format you have ie zip disk, cd or floppy, you ultimately will have to use floppy since you dont have a zip drive or cd rom.
So if you get sounds that come in cd format you can copy them to a bunch of floppys. (very long process)
When you convert them to floppy, put the floppy into your mpc floppy look at the numeric buttons with the different events i e mixer, program, disk etc.
You then want to press and hold shift the press the "disk" button. Your sounds will load. Use the jog knob to browse through the contents of your loaded disk. Press do it whenever you wanna hear the sound before you actually assign it to a pad. A menu will come up and you can play the sound, discard it or keep it. Once you find a sound you wanna keep, press a pad you want the sound go to and press keep.
Its real simple.
Akai MPC2000XL l Yamaha Motif 6 l 20" IMAC Core Duo 2 l Tascam FW1082 l KRK Rokit 8 Monitors l LOGIC Express 8 l Reason l