Personal training session - advice on what to ask?

Newbie post..

I've been working on losing weight for the last few months and it's slowly but surely happening and I know it's a long journey..

I recently rejoined the gym after not being there for a year or so and I have a session with a personal trainer coming up to work out - routine etc

I have been mostly doing cardio and swimming on my own, I also try to walk at least 5k a day but I guess like most people I would like to start working on building some muscle and getting a bit stronger..

Just looking for advice on what I should be looking for from a training session, what I should ask and what I should really be eating before a training session - i normally eat a lot of protein, lower carb and try keep my sugar on target .. What should I be looking to be eating before a training session? I suspect it will be quite heavy so the PT can assess my limits?

Like I said - newbie post so any advice is welcome! Thanks.