It's a hex nut just below where the nose drive meets the main case. That's an M-62 and it takes about one bottle. PN 12345982.
Use a turkey baster and hose to suck the old oil out. I change it every other engine oil change, but it's considered a permanent lube so don't panic. Fill to the bottom of the fill hole.
The old oil will come out green (normal). The new oil is clear. It's also normal to see seepage around the pulley which gets covered in black belt dust. Just wipe it off periodically.
