Underrated Topic. I was working out for only about a month a while back, lifting weights and walking around town for 1 hour early each morning this summer (because of the heat). And it's still pretty surprising how well something as simple as that was enough to make me build muscle quickly. When I started, I didn't research how to exercise properly and learned mostly overtime from my family and through trial and error, until I eventually looked it up online for the stuff like how to do lunges/squats the right way. Not sure if it's a problem with my knees and shins, but when I blindly tried doing squats without knowing how to do them, it
really 
ed up my legs for a solid week.
The two points I was trying to drive home was that once you get into the habit of exercising, it becomes a lot easier than just starting it out of nowhere. And the other point was that you should definitely do your research before doing exercises that you're not familiar with doing. You can hurt yourself that way, but I'm sure most people aren't as... we'll say, "silly" as me when it comes to this.
One last thing, consuming protein is mandatory to build muscle. There's no way around it. Personally, I ended up buying some big 5 pound tub/jar of protein powder and made sure to follow the directions (on the jar) as best as I possibly could. If you can't do that, then Peanut Butter, Meats, and I think tuna fish has good to decent amounts of protein in them. Oh yeah, and eggs.
I

ing love eggs.