First time going to the gym tomorrow and nervous.

First I have to admit , I am on Mounjaro because I just came off prednisone after 7 years earlier last year. I would lose and regain the same pounds back. I'm 32 years old btw.

The first picture is me at 300 pounds back in August of last year. I am now at 210 pounds in November this year. I did lose my hips and "some" butt which I want to build back lol.

I do have extensive heart and lung disease, but everyday I walk 8,000-10,000 steps every single day. Now I want to rebuild my glutes/hips back and target my stomach which is why I know the gym is the spot. My insurance pays for me to have a gym membership. 

My questions are: is there any specific machines I should get on to target what I'm trying to do?

Any proper gym etiquette that I should know about?
I struggle with protein a lot. Any recommendations for a powder or the pre-made ones? I've yet to find one i like.
I dont have workout clothes yet, but I do have leggings and tank tops. Will that be fine?

My weight goal is 170-180 pounds. So I know now is the time to get my body toned up. Basically im down for any solid advice, tips, and overall just any information to help.

Also, I do have ankle resistance bands i just bought . Nevertheless, sorry for the long post. Im just so nervous and to make sure im doing it right. Thank you in advance!!

Posted in r/gym but wanted to post here too.