I dont know of a manual that shows you how, but I might be able to help you. You probably need simply new seals, and oil. The dropoffs, which are ssv damping, usually dont have a cartridge unless it has a rebound adjustment.

Here is a similar fork. The dissasemble is basically the same, as is installation/removal of the seals.
http://enduroforkseals.com/id27.html

I also recommend the seals from this website. They get nothing but praise from people who use them. You would need the 32mm version.
http://enduroforkseals.com/id20.html

You need a thin-wall 12mm socket to remove the lowers. Marzocchi sells this for 25 bucks, but it is easier to buy a normal 12mm socket and grind it down. You also need a 19mm, and you might need a 21mm socket. It depends on what topcaps you have.

For oil, go to a motorcycle shop and look for 7 or 7.5 weight fork oil. It is alot cheaper than buying it from marzocchi. Marzocchi's factory fork oil is actually Golden Spectro, but it gets more expensive with a Marzocchi sticker on the bottle.