It's all fairly simple to do. What's the amperage of the panel in the garage? Should be a switch at the top that says 60 or maybe 100 amps (might be at the bottom). How many open spots in the panel. What tools do you want to run in the shop. Black and Decker sells a good book on electrical wiring. That's what I started with. I just wired my entire shop myself, meter base, panel, 5 ton AC, lights, welder outlets, everything.

Insulation comes down to how much do you need and buying the right width to fit between your studs. I prefer kraft faced using a staple hammer.