What you will need to do is find an instructor with enough bike fit experience to properly fit you for the bike.
At my clubs, every new person gets a bike fit by me. I have a goniometer, and I measure seat height, leg angles, torso to arm angle, and upper arm to lower arm angle. I also check to make sure the balls of the feet fall over the center of the pedal, in the downstroke, then I also check for the roundness of the pedal, as well as give instruction on smoother pedalling techniques. This does not count the introduction to the indoor bike and the coaching on hand position, body placement, and weight placement.
That's the first class, but the instruction continues through all classes. I do a lot of interaction with my riders in class. Sometimes, I even bring in cycling articles for them to read so they can learn more about how they can use cycling for exercise and how they can get into cycling outdoors.
Koffee