missing Staple tool

You do it a different way now. You nest the layer you want to attach in the layer hierarchy, then set “Attach To” to “Auto”, and use the “origin handle” (Dotted line cricle) to drag over the attach point of a parent layer (the origin handle should turn green to indicate attached correctly).  This recent thread happens to have some screen shots that might help (Hand dragger forearm and bicep ), but there are lots of tutorial videos etc around as well. And the user guide of course. But its not called staple any more - you use nesting plus “Attach To”.