Congrats! My recommendation in working w/ a reputable trainer is that if you don't understand the reason WHY for something, ASK! IMO what you're also paying for is to learn some new tricks and also some insight into interpreting how YOUR body responds and what works. I also don't think there's anything wrong w/ asking and re-asking if you don't get it (whatever it is that you might not get the "why" on). A good coach can explain why.
Best of luck! It is awesome to have someone w/ an experienced eye work with you because competition is such an esoteric thing to judge "progress" on. IMO its particularly hard for women because its not just dialing in to get as lean as possible - its more about getting the right balance of leanness, muscularity, symmetry and femininity for your chosen category. And then just getting it all presented nicely on stage!