I had a professional coaching experience last fall, my only one. I have no idea how your coach will work with you. This is what mine did. He put my bike on a trainer and had me warm up and then had me ride as hard as I could for five miles (totally not fun on a trainer .. much harder than on a road). He observed my riding style, cadence and a bunch of other stuff.

My goal was simple, to get faster, particularly on hills. He gave me some tips on pedaling efficiency, position on the bike, breathing, etc. We talked about my goals, what is "realistic" for me like how many times a week I can reasonably ride, what types of rides I do and how I can incorporate training into what I was already doing, like doing intervals while on a weekly club ride.

Then I went home. He came up with a training schedule for me and mailed it to me with descriptions of how to do each ride or floor exercise he wanted me to do. (Didn't do the floor exercises. SO not part of the "realistic" part of the training plan for me!!!)

This was supposed to be about an 8 week plan and, if I continued with training, I'd come back in and do it again. See how I improved on the trainer and get another 8 week training plan.

So, that was my experience. Yours could be completely different. Just think before hand what your goals are. Write down every question you can think of. Your coach will help you figure out how to best use the session(s).

Good luck!