I have just started back to the gym after a multi year long break. I like the treadmill for calorie burning and the weight machines to build/tone muscle. The treadmills can be boring, but many of them have a TV screen and are online. (my gym is the YMCA) I watch TV or catch up on some of the you tubers I watch. When I started back (actually, last week), I made an appointment with one of the trainers who showed me the machines and set up a workout program. The fitness plan can be accessed online through my phone and I can record my workout. Makes it all real easy. I would prefer to be outside, but we have just had our longest rain free streak since September (4 days), so the weather doesn't cooperate sometimes. In the summer, when it cools down to 90 F everybody goes outside to enjoy the cool day.
Ask your friend to invite you again! I'm sure they would be happy to go. Having a friend will help you push yourself a little more. When your friend can't go, build you self control muscles and push yourself a little. Be open to gym friends (I need to work on this LOL).
Don't let the machines intimidate you. Your friend can show you what to do, or you can make an appointment with a trainer to learn how to use them. Most of them follow the same protocols for use and have diagrams on them to remind you what to do. If a machine gets overlooked during your introduction but you want to use it, watch others or go ask someone using it (when they are done, not during their work out).
The gym I go to is the same gym I went to before my long break, They did a good job keeping the...ummm... less desirable, rude, show off types. See if the gym you're interested in has a free trial period and use it to watch the culture of the gym, but the gym your friend goes to is probably good since, as friends, you will share certain expectations.
Some people worry they will be judged by others at the gym. No, you won't. Everybody is there to improve their selves and some of us have further to go than others. I am borderline obese and I wear yoga pants and racerback tops and have never been made to feel uncomfortable.
Once you get into the routine of regular trips to the gym, you will find you feel better the rest of the day and the next day. I really don'y know why I got out of the routine, but I regret it now.
So go. It's fun. You can socialize with your friend or meditate on the answer to Life, the Universe, and Everything. You'll feel better about yourself and everything else.
Sorry this is so long.