Disney recently introduced days the fastpass+ system which means you can book 3 fastpasses for any one park on any one day up to 30 days before your visit. You log onto My disney experience, link your tickets to your account then get the fastpasses. I just wanted to alert you to potential problems that we discovered. We have old non-expiry tickets and because they were not the right type, they didn't have a QR code (or so my son tells me it's called!), we had to take the tickets to guest services to get new ones issued before we could use them on the system. We did this on the first day of our holiday and then logged on to get fastpasses. We wanted to try out the seven dwarfs mine train but there were no fastpasses left for that for ANY day of our 2 week holiday!
So be aware and as soon as you get your tickets, decide when to go to Disney and book your fastpasses for those days!