It doesn’t have a tutorial as it isn’t configurable. You put the behavior it gives onto the objects you want to sort, make sure they’re on the same layer, and then they both sort based off the Y position of their Origin points.
So as your player moves down, as soon as their Origin Point’s Y position is “higher” (actually lower on the screen, because Y positions increase as you move south), it’ll appear infront of the Tree.
If it has a lower Y position, it’ll go behind the tree.