Headed to the gym for the first time since high school... How do I not make a fool of myself?

I am about a year into my weight loss and I am 55lbs down. In recent weeks I've noticed that I have finally lost enough weight that the burden on my joints doesn't leave me stiff and practically unable to move by the end of the day. Non-scale gains yay!

In addition, I have reached a bit of a plateau in my loss, so I bit the bullet and signed up for a gym membership. My day job is fairly active, and I am usually able to hit my 10,000 steps just from a typical workday and that was enough activity up until this point. I'm interested in slowly increasing my physical activity with strength training preferably so I can build some more muscle and increase my BMR.

So like the title asks, how do I do this without making a fool of myself? I haven't been in a gymnasium since high school in the early aughts. Zero knowledge on proper form, how the various machines even work let alone their names. That would all be okay, I guess what I'm most nervous about is breaking some sort of unwritten gym etiquette code or something. I'm a naturally quiet, introverted person so even getting over the hurdle of committing to work out in a public place where strangers can see me is a feat in an of itself.

What tips/tricks/rules can you guys share with me that will increase my confidence going in for the literal first time in my life? All feedback is appreciated!