We just used the AAP (orange card) over President's Week. It is similar to the old
DAS system at Disney where you physically go to the ride and request a return time from a Team Member (TM). If the ride's standby wait time is less than 30 minutes, you are granted immediate access to the Express Pass Line. If the ride's standby time is more than 30 minutes, the return time is calculated as that wait time minus 15 minutes. You return at that time and use the Express Pass line. Like the DAS, you can hold that return time for as long as you want until park closing. You can only have one return time at a time, and cannot use the AAP to access a different ride's Express Pass Line while holding a wait time for something else. One issue we had a lot of trouble with during this busy week was the Express Pass Line was often longer than 30 minutes long, thus negating the whole purpose of the pass. We'd often wait an hour or more for a ride only to be put into an Express Lane that was over an hour long. In that case, we should have been given front of the line access, but the TMs were rude and dismissive. TM were awful about helping when that occurred and I've contacted GS about it. It's something they really need to address when the parks are that busy.
The other pass is GAP, I think it's yellow in color, allows for immediate access, but wasn't something we really needed.
I was able to call GS ahead of our trip and speak with a TM in the accessibility team about our needs. She set up our pass over the phone, gave us a reference number to give to GS in the park. I walked up to GS when we arrived and it was a quick 3 minute transaction to scan all our tickets and the pass to our account, and done. I have to say, I much prefer the new DAS at Disney being on the app! what a time suck walking to the ride for return times. We did both this trip and as much as we love our coasters and thrill rides, we'd pick Disney over Universal for the ease of use.