It should be distributing points on the outermost faces of your mesh, working its way inward as you adjust the To Min value on the Map Range node. If you want to get a good idea of what it’s doing, just plug the Points To Volume node into a Join Geometry node to get a nice visual representation of it working.
It should work on anything that has faces to distribute points on. Like here it is on a cube.
If you still can’t get it to work, post some screenshots of your problem, and I’ll see if I can help you out.
Oh, and I made my trees with Modular Trees 4.0