It sounds like your crank case is leaking along the horizontal seam. You'll have to split the tranny to fix the leak; if that is indeed where you see it coming from; you could clean up the oil and torque all the tranny bolts and check it again; after some riding and see if it is still leaking. Unless it is already out of the bike and partially dismantled then...
It would be a good idea to break it down snapping off a lot of pictures as you go; that way you can see how everything was at each step and bag and tag all fasteners and parts that group together.
If you turn the crank with a wrench you can get the cam chain master link in a good spot to ease it off; just keep going taking your time til it is dissembled, it's not a very complicated motor, every part has a clear function and is minimalist as to what it required to function well.
So take some breaths and don't let it overwhelm you, and have some confidence. If you can take it all apart then; it's just as easy to put it all back together. The pictures, bags, and tags make it a cinch. I used to not need to do that...it could have been more than a year, and I'd know right where everything went. Funny thing about age; you don't see the peak until you're already over it, flying down the other side. I am trying to enjoy the downhill; enough to take my hands off the bars, and feet off the pegs, and not look back
