I think the MOST critical thing first is to start slow and make sure you are using proper technique. Don't put much stock into those preplanned workouts. Everybody is different. Start slowly and stay patient. Do basic workouts and take days off, sleep, and eat clean. I've never been a fan of machines. I've seen way too many people hurt their joints more than help on those. If you can find someone to show you how to do PROPER deadlifts, squats, bench and all that stuff then you'll be fine. I love olympic lifts and explosive stuff, but I find a lot of gyms don't allow it now. I'm an advocate of practical strength and fitness, which usually doesn't entail cranking away on the bench press all the time. One thing, as dorky and pointless as it seems, is to work on grip strength. It can be indirect when doing deadlifts, but a strong grip always seems to translate into better lifts in other areas. Once you reach a plateau you can start doing all the other stuff. Then you can do HIT, accommodating resistance or whatever else. I love working with bands and chains, but it is a good way to hurt yourself if you jump into it.
Since you are a skinny guy, you are probably going to have to just eat a lot. I've never been a fan of protein powders unless you absolutely need it. If I knew I couldn't get around food for a while then I'd make protein bars and munch on that to hold me over. But once again, the important thing is to stay safe and be patient. Don't jump in, load up plates, and kill yourself. Also, finding a partner with the same goals is great. Those days you don't feel like going to the gym get much fewer when you feel like you'll let someone else down.