First Trip w/ Magic Bands and new FP system

Once you use those 3 or their time expires, you can go to a kiosk and try to schedule an additional FP and then once it is used/expired you can again go to a kiosk and schedule another. You can only add one additional at a time and use it before you can get another. You can't get the additionals through the app, you must go to a kiosk. However, don't waste your time because all that will be left at that point, if anything at all, is the rides and shows that you can walk right into anyway.

One tip I would add is to make your FP ressies for late morning/early afternoon. You can walk on to rides with minimal wait in the first hour of park opening. Then later in the morning when the lines start to pile up use the fast passes then. I've had success getting fastpasses from the kiosk after I've used my original three but I suppose that all depends on how busy the park is that day.