Hi, Chuck52
Here are installation instructions from the 1951 Accessories Installation Manual. pp36-38.
Do a search on Stovebolt forums for "heater". You will find a wealth of info. Post your questions as they come up. You will get good advice. Brad Allen is a heater guru.
I learned a lot when restoring and installing the heater in my '54.
Here is my saga. with some good links included in it.
BTW - Measure the diameter of the defroster vent ports and the heater defroster outlet ports before you order the hose. Some are 1-3/4", some are 2".
Good luck and welcome.