The part with the two notches is left-threaded, so clockwise to loosen from the perspective of your picture.
It should be noted that these are quite the can of worms once apart, and cleaning/lubrication can be done pretty effectively by taking the whole freehub body off using the 10mm internal Allen wrench flats (poke a 10mm Allen into the hole in the center of the freehub; that part is normal threaded). Then on the back you'll find a rubber seal. Carefully pry that out and keep track of its orientation. Then you can easily blow or drip air or whatever lubes/cleaners you want into the mechanism.
The one thing that can't be done this way is take advantage of the seldom-discussed cassette play adjustment that Shimano freehub bodies have. To do that you remove one of the thin shim washers you find inside the freehub internals.
If you do take it apart you must answer the question of what you're going to use to keep the ball bearings in place when putting it back together that's also not too thick for the purpose. You don't want regular bearing grease in there because it can gum up the mechanism. The main thing I know that works is a thin layer of Slick Honey or similar very light grease.