Hi..hope this helps.. I downloaded an app onto my phone called Apps2Fire. Then downloaded onto my phone the disney+app both from playstore.
I bought a firestick and plugged it into back of my TV...I then set the firestick up on the TV. Then I opened the apps2fire app on my phone and connected to the firestick Then simply transfered disney+ and any other app I wanted to the firestick...
I also downloaded from playstore an app called downloader..and one called Firetv
The first is a remote control for the TV using my phone..I play pranks on my grandchildren using g it by changing the fav channels to something boring lol.
I've attached a photo showing the apps...hope this helps