Go full body and light
One session hitting legs, push, and pull teaches you the gym without wrecking you. Machines guide the path so you can focus on control rather than balance while you are new.
Keep it simple: a short full body session of a few machines, learn the movements light, and leave with energy to spare.
Do not overthink day one. Pick 5 or 6 basic full body movements, mostly machines since they are easy to learn, and do 2 sets of 8 to 12 reps each with a light weight to learn the pattern. Something like leg press, chest press, lat pulldown, seated row, and a shoulder press covers your whole body. Leave feeling like you could have done more, that is exactly right for the first day.
One session hitting legs, push, and pull teaches you the gym without wrecking you. Machines guide the path so you can focus on control rather than balance while you are new.
Your only job on day one is grooving the movement. Keep 4 or more reps in reserve, move slowly, and it is fine to ask staff or watch a quick demo for setup.
You will likely be sore in 1 to 2 days, that is normal for a first session. Book your second visit for 2 or 3 days later and repeat a similar full body plan.
Keep it simple: a short full body session of a few machines, learn the movements light, and leave with energy to spare.