It is a process that is simple in theory, often is simple in practice, but can be a real PIA. Unfortunately mine wasn't simple. The pins that hold the sight base in place are tapered and will only come out one side (they have to be driven out right to left), after driving them out you remove the sight base. This can be done with a press, knocking it off with a hammer, or even a two by four. Then you press the new sight base on (once again the tools of choice seem to be a press, hammer, or two by four), and adjust it to get it verticle. Then you must drill the sight base to make holes for the pins that secure the sb to the barrel (a new sight base won't have these holes). Reinstall the pins and you are done. It is recommended that you use a drill press to drill the holes, but many have done it with a hand drill.
On mine the pins would not come out (this is something that varies from gun to gun), and I ended up having to take it to a gunsmith to have the sight base cut off. I had him install the sight while he was at it. If you have to cut the base off then you will need to replace the two 3mm x 12mm.
My receiver looks and functions great. The conversion from a low capacity to a high capacity receiver was well done. I have pictures of it that I'll post when I get back from class.
Kyle