I had initially started lifting in my garage because I had a bench press in there and some free weights. When you do it this way, it's really hard to motivate yourself to go and do it every day.
When I sucked it up and joined a gym, I was working a lot harder and was far more motivated because there were people around me. The atmosphere is just far more welcoming because everyone around you has a similar goal, and I believe it's the only way to see true gains.
I would suggest you go to
www.bodybuilding.com and look up the "exercises" tab where it shows the anatomy of the Human muscular structure.
Pick a muscle group, like the pectoralis major, pectoralis minor area of the body, and write a few of those exercises on a piece of paper, then go to the gym and do it. Do the same for the arms and shoulders. You don't have to look up exercises for the legs, because most gyms have like 5 different leg machines. Just rotate those. You don't have to worry about switching up your exercises for like the first 2 months. Your body is new at lifting so it wont really adapt at all.
Since you state that your skinny, you will literally see huge gains after the first 3 weeks, and your confidence will sky rocket. Everyone who sees you every two weeks will notice your improvements if you do it right. Even if you don't exercise 100 percent correctly, because your a beginner, you'll still see gains.
I know you don't want to take anything, but... If you have energy problems, which most people do when they start, you could take creatine. Creatine is stored in the cytosol of muscle cells as phosphocreatine (PCr) and is important in short-term adenosine triphosphate (ATP) production for muscle contraction.
After our body uses ATP(Adenosine Triphosphate) it becomes (ADP)Adenosine diphosphate, and it loses its phosphate. Creatine is phosphocreatine (PCr) and lets (ADP) use it's phosphate which synthesizes it back into ATP, so it can be used as energy again.
Creatine won't help you with exercises that are more than 60 seconds, so it wont help you get muscular endurance, only muscular strength. Water retention in creatine is a side effect, and completely over dramatized. As far as i know, the most water retention you can hold in the muscles is 1 lb with creatine. When people say that creatine users muscles are full of water, they just sound retarded because muscle is 75% water. You can't really overdose on creatine, since a 200 lb man can only store 10g of excess creatine. Any more than that, and you'll just piss it out.
I don't recommend taking creatine if you have the energy to lift naturally. But you will be notably stronger with creatine in short burst muscle contractions.
Sorry for the bad paragraph form, i'm in a rush to study for my finals. I just had to comment because people were joking about something that could be both mentally and physically beneficial to you.