To find out the difference between "road", "Mountain", "comfort", ... Pick a brand or two like Trek, Bianchi, Specialized, or whatever and go to their websites.

The club idea is great you need to find folks to talk to. They will know what shops won't try to sell you junk.

Ride lots of bicycles - some of each type so you can feel the difference.

The rehab folks will have you do lots of different motions and will know when you should start on a stationary bike and then to a real bike.

Going to some shops while still on crutches might be very informative.

Good luck and welcome to the club.

Joe