It can definitely feel intimidating. As someone who would categorize myself as a "gym girly" now I will tell you that not one person in that gym started where they are now. They all were beginners at one point, they all fumbled to figure out the equipment, they all made mistakes. Heck I still drop weights, forget how to move stuff, etc. Also, most of us are so focused on what we are doing that we aren't paying attention to those around us.
I will also say that most gym people love helping people. We love talking about fitness and sharing knowledge and I am sure many people at your gym would be happy to help you out.
A lot of gyms also now have the QR codes on the machines that show you how to use them and some gyms like crunch and planet fitness have preset workouts on the app that you can walk through.
My next BIG thing though is going to be about safety. Your diet pre-op sounds VERY calories restrictive and chances are you're not going to have a lot of excess energy for activity at that low of a calorie intake. So many sure you feel up to it. If you feel tried, lethargic, dizzy, have a headache, etc. I wouldn't do a workout. Your body is trying to just function at that stage and might not be up to the excess activity just yet.
I am really into post bariatric fitness and just got my certificate in nutrition health and wellness. Reach out anytime on IG @ anastacia_bari_life