Brand new gym goer!

Hiya, rather than try to stitch together a strength training program from hodge podge internet advice, it might be easier (and a more efficient use of your workout time ) to follow an already established, proven workout schedule. Something like Stronglift 5x5 or the beginner weight lifting program from these guys https://www.aworkoutroutine.com/the-beginner-weight-training-workout-routine/
And definitely ask a trainer at the gym to help you with form and proper use of the equipment, you don't want to end up with an injury.

I'm here for two reasons:

1. To let you know there's a thread here where MFP users discuss and compile a list of strength training programs that have worked for them. It's here:

http://community.myfitnesspal.com/en/discussion/10332083/which-lifting-program-is-the-best-for-you/p1

Despite the title, it's not just free weight programs, if that's a concern. Niner's right, though: Form is important, and a trainer can be a good starting point.

I was able to take a group class to start that was not the common "everyone do these exercises simultaneously like a dance holding heavy things". Instead, it was one where an experienced trainer taught form for exercises, then individually worked with us on form. He would go around the room as people did different exercises to give individual attention, but also was scanning for people doing something seriously worrisome. It was more affordable than a one-on-one trainer, but still quite useful IMO. Perhaps there might be something like that near you, if a one-on-one trainer is difficult to budget.

2. I want to encourage you: I started being active at very close to your stats (5'5", 180s-190s). It was in my mid-40s, after treatment for pretty advanced (stage III) cancer - surgery, chemo, radiation and the whole 9 yards. I was seriously out of shape, and had a history of drinking more alcohol than was good for me (problem drinking, probably not all the way to alcoholism), and routinely using some of the lower-risk illegal drugs for around 20 years.

So, not exactly your situation, but pretty compromised health. It was a slow thing, getting gradually more active and fit over a few years, and then 10+ years later finally getting to a healthy weight. Now, I don't think I flatter myself when I say that I'm fitter than average for my demographic. I've competed in races (rowing), even won some place medals, which is startling for someone who was once a "chosen last in gym class" kid.

My message is that you can do this, and if you can stick with it, focus on patient progress, you can amaze yourself with where you find yourself in even a few months, let alone where you may reach as months become years. The quality of life rewards are huge. I'm cheering for you!