HELP-2002 Cavalier Elecrtical Nightmare

I have a 2-door Cavalier with manual locks and windows. I want to convert those into power locks, windows, and add an alarm system. I don't know much about electrical, so any information would be appreciated. What brands or products, and how-to guides?

Also my stock cd/radio works only partially. At random times it will turn on and work for a minute or two. I have had the car since January and I have heard maybe 10 minutes of audio. The unit recieves power because the display is on, but nothing comes out of the speakers. Wiring problem or bad fuse?

And since I am talking about electrical. My horn doesnt work in my car either. I dont even know where to begin on any of these problems. I don't have much time to figure them out myself since I work and go to college. So any help is appreciated. Thanks.