Yep...do exactly that. Assemble them on the ground and lean them into the tree. Strapping them around the tree once your going up. Slick and easy. Now the somewhat difficult part is hanging the stand. Loosen up the strap that goes around the tree far enough so that when your up in the tree, you don't have to loosen it up anymore. Tie a rope to the stand, climb up and hoist it up. If you have a quality safety harness(HSS more specifically), it will be setup for you to convert it to a linemans belt. This makes everything faaar easier. Put the stand around the tree, put the hook on and tighten it up. Before you actually stand onto the stand, lift up the platform of the stand and simply put it back down. The stand will move down a touch on the tree tightening itself really snug against the tree. Make sure that the V parts of the stand are into the tree. Not a big deal if they aren't, but your stand will be more solid against the tree if they are. When climbing onto or off of it, just be sure that you try to stay away from the very side backward edges of the stand. A stand not solid enough against the tree and the stand will rotate outward from your weight. This is where guys have potential of falling out of your stand. So just be aware of what your doing at all times.
I put about 15+ lock ons up a year, so things have become fairly standard. And most with the standard tree steps. ha, ha
I hope all this makes sense. Good luck and if you don't own a safety harness.........GET ONE!! Hunters safety system is one that I recommend hands down. Yes...they are spendy, but our #1 goal during every hunt is to make it back to our loved ones just as we left. And this includes hanging stands for a hunt!!