How is Fit24 [Nishinomiya] for someone who has never stepped on a gym?

Edit: thank you everyone for the fantastic answers and patience. I feel really motivated to start, thanks!

Original post:

I would like to join a gym to exercise, grow some muscles and improve my posture. Any opinions on Fit24?

My main requirements are free parking, being able to enter with outside shoes, and free cancellation at any moment (no yearly fees), all of which Fit24 fulfills. It's 8,000 a month, no idea if that's a good price or not. And is insurance for 500 yen a month extra worth it?

I don't have any tattoos, so that's not an issue.

I worry that I have no idea how to do any exercise, use any of the machines, or about gym etiquette in general (wiping the machines after use and so on). Are there staff to explain these things or do I need to pay for a personal trainer? How about an exercise plan, is it included when you join? I didn't see it offered as a separate service (maybe it's not even a choice).