Well, you have to split the cases to clean out the bottom end. If you never did this before, get a tech manual for the bike. Its really not that bad once youve done a few of them though. Alot of manuals will say to use a special holder to hold the inner clutch hub as you break the nut loose, if you have a compressor, usually you can just use an impact gun on this, no need for the hub holder. But yea, once you split it, remove the crank, wash it in a parts washer, thoroughly. And be really careful checking the crank bearings. They are what just toasted a brand new top end on my RM ...
Once you clean the crank, the cases are nothing special, spray with break clean, wipe with a fresh, clean, lint free rag. Get all the pieces out.
Lightly coat all the new parts with oil. And dont cheap out on it, buy new gaskets. Or at the very least, use "The Right Stuff" as it seems to be the best silicon on the market right now ...