Phil,
Prayers and good wishes are coming your way. Look how far you have come.
When you join the fitness center they will sit down with you and take your medical history and what your goals are. From there, they will recommend a trainer for you. (that's what my experience has been) You can also go and just use the cardio machines and check out the trainers as they work with other members too. You might see a trainer that you like the way they interact with others. The trainers are all certified.
Lots of luck and let us know how you make out.