Recent 10/22s are drilled and tapped for scope mounts and the rear part of the Tech-Sight uses those holes in the receiver. Just remove the protective screws from the receiver, put a little Loc-tite on the new screws, and screw the rear sight in place.
To install the new front sight tap out the old one. The instructions say to use a brass punch and hammer. I don’t own a brass punch, so I used a steel punch I had handy and covered it with two small pieces of duct tape to keep from scratching up the old sight. A half dozen taps pushed out the factory front sight.
The new front sight didn’t want to go in. I used a file to lightly file down the leading edge of the new sight using about as much pressure as you’d use to file your nails. One stroke didn’t do it – it still wouldn’t quite go in. After the second stroke of the file I was able to get the front sight into the dovetail. I only took a tiny, tiny amount of material off to make it fit. After the front sight was in I used the supplied set screw and hex head wrench to screw it into place so it wouldn’t come loose.
The factory 10/22 rear sight is located on the barrel. The Tech-Sight rear ditto is on the very rear of the receiver. That adds about eight inches to the sight radius, which helps a bit with accuracy.