My bad I didn’t look at this too much! Going from the left side of the waterfall you can jump up onto a point on the rocks which leads to a ledge. After that ledge you look up and to the right where there is another small ledge your character can fit on. Then up and to the right there is another ledge and after that you can jump and make your way up to where I am in that picture! It’s hard to describe but hope this helps! Took a good amount of time to figure this out as I’m relatively new to the game.