>>88148 (OP)I've been going to the gym for two years now, went completely alone and without knowing how to do anything, here's my advice.
First of all, I was skinny. If you're fat, do more cardio and focus more on diet stuff. I just forced myself to eat more & focus on building muscle, so I can't give advice for that.
I recommend starting with machines instead of weights. They provide more control, less risk of injury, and if you're scared of looking stupid or whatever, that's not really possible. But you can always just do whatever you're most comfortable with; that's just what worked for me when I started.
Even if you try to look up how to use the machines beforehand, chances are you'll forget, or there will be ones you didn't read about, or whatever. You can usually get a trainer or whatever who'll show everything to you for your first day there, but let's assume you're too much of an asocial sperg to do that, as was I. You can always just watch people out of the corner of your eye and see how a machine is used. And you don't have to be a sperg about it, just when the opportunity comes up you can do that.
Like the last dude said, always start with way less weight than you think is "right" for you on your first time using a machine, and increase after like 1 rep if it's too light. The only embarrassing thing you could do is try to ego lift, setting the weight purposefully low and increasing it bit by bit through a couple reps to find the correct weight is fine, and in the extremely rare chance that someone is at all paying attention to your existence, that just makes you look like a competent newbie, as opposed to an incompetent one. Trust me.
Hmm… idk what else. Wear shorts and a t-shirt. Put your phone in your bag (or a nearby safe location if it isn't populated by apes), not in your pocket while you're working out, it'll feel awkward and you'll immediately get it. I prefer drinking coffee (but not eating) before going in the mornings since food will make me feel like I'll vomit, and then having protein powder post-workout.