Welcome to the forum, Matt.
You might be in over your head if you don't take some time to educate yourself on proper shower waterproofing. Easy enough to do hereabouts, though, if you're willing to put in the time.
And if you can't find what you're looking for, or don't completely understand what you find, that's what we're here for. You can start your own thread (which you've already done) and ask as many questions as you want.
I would advise you to move over to the
shower construction thread in the Liberry and start reading up on how to build a shower. If, after reading everything there, you feel completely overwhelmed, it might be best to consider hiring someone. There will be a lot more to remodeling your bathroom than what you'll find in that thread, but it's a good place to start.
You'll begin by choosing a waterproofing system, then move forward from there.