I follow a few lifters on Insta:
MegSquats, who sells a programme called Stronger by the Day ($US80 or so per year, so about the same as 2 months of gym fees!) It's free to try for a week. There is huge variety, and really good instructional videos. It's a week by week programme, so you just follow it.
Also:
I really like HenleyFitness - run by a very funny (and quite potty-mouthed) young woman called Rachel Henley. Follow her and she will send you a free programme if you DM her I think.
Both these programmes use barbells, but suggestion substitute exercises which use machines. HenleyFitness Insta feed is good on showing you in short videos how the machines work. She focuses on those who are scared to use the gym for the first time.
Do a bit of watching & reading, then book an induction at your local gym, and go with some ideas & questions. Let the gym trainer who runs your induction know what you want to focus on and ask for some guidance about how to construct 3 workouts a week.
Roughly a work out for an hour should have maybe 5 -10 minutes warming up - using a static exercise cycle for 5 minutes, or running/walking on the treadmill (put the incline at 2) at a pace which gets you a little warm, but not puffed out. Also then do some mobilising exercises: swinging arms, swinging legs (forwards and backwards, and across the body), something like squat jumps or burpees (just 10 of each).
Then maybe one day focus on legs: a form of squats (weighted barbell, dumbbell goblet squat, leg press, slit squats with or without dumbbells, lunges, with or without dumbbells or a sandbag across your shoulders); hipthrusts; some sort of hamstring curl; some sort of leg raises/leg curl (both can be done on machines). Then stretch and mobilise for 10 minutes
Day 2 (after a rest day) warm up & cool down the same, but maybe do a "push" day: Overhead press; dumbbell push press; dumbbell thrusters; bench press. If your gym has a sled & sled track, that is fantastic for building strength really quickly and with little or no technique, other than grunt.
Day 3: (after a rest day) warm up & cool down the same, do a "pull" day: the deadlift is the major compound lift that is classified as a "pull" and they are fantastic for your whole body. You can do RDLs (Romanian dead lifts) with dumbbells or a sumo deadlift with one dumbbell (go as heavy as possible). Lots of upper body pull movements with the cable machine, and also the brilliant lat pulldown on a machine - trains your back for pull ups.
You can use YouTube or Insta to get ideas & tips on good form for all the compound exercises. THere's lots of good advice there.