Step 1: Remove barrel - Remove the cap on the end of the mag tube, unlock the action (ie: slide pump towards stock) and pull barrel off.
Step 2: Remove slide bars/forend and bolt. This part is tricky. Basically, you need to move the slide forward, while depressing a little part inside the receiver (I think it's the 'shell retainer' just outside the mag tube). The bolt and action bars should come out together.
Step 3: Remove trigger pins. This part is easy. Simply find a punch/screwdriver and lightly tap the pins out (either way, although one way MIGHT be easier). Once the pins are out, the trigger group drops out.
This is the extent of which you should strip it down. Don't mess with the trigger assembly, as a simply light brushing/degunking will be more than adaquate.
For more details, check out the Remington website. They will CERTAINLY have a better writeup than mine!