MANO has a tutorial about this under the tutorial section. Look under the MPC 1000 MixDown. Once you do that save it. If you need help saving, watch his 1st video on the MPC 1000. After doing this, if you connect a USB cable from the MPC 1000 to your computer.
Press MODE
Press LOAD(pad 2)
Press USB (on the screen, should be like F4 or F5)
Once you have done this, I pop-up should come up on the bottom right hand side of your computer, saying that the MPC1000 has been connected. Click to view folders.
Now find and select the audio file you just mix down too and drag it to whatever file you want to save it under on the computer.