I would suggest that you check out the video from AGI on the Ruger pistol. Also you might get a copy of "The Gun Digest Book of Firearms Assembly / Disassembly - Part 1: Automatic Pistols" before doing anything else.
There is a story going around about three men of the cloth walking through the woods discussing their disparate theologies. They come to a river and the first declares, while adjusting his roman collar "I shall cross the river." And he walks across the water to the other side. The second, as he adjusted his yamaca, declared "I too shall cross the river." And he too walked across the river to the other side. Not to be outdone, the third declared "If they can do then if I have faith, so can I." He steps off the bank and sinks up to his neck. He swims and as he emerges on the other side, coughing and sputtering, the Rabbi leans over to his dry companion and says, "Father, do you think we should tell him where the rocks are in the river..."
The point is that it is easy to walk on water if you know where the rocks are. And one of the reasons we direct folks to gunsmiths is that they know where a lot of rocks are. But failing that, for easy jobs, AGI videos and a lot of reading material will help...