I had no idea how this was done so I watched curiously. First the hole in the wall was squared up, then a piece of drywall with paper on the back was cut to the size of the hole then screwed in, then mudded over then let set. Dave advised it would sink in and would need a 2nd coat after it dried, then it could be painted. On the smaller area where it was more a dent than a hole, he was able to just mud it over.
(I have to give Marv a shout out as he traded skills to get this done).