Hi there and welcome
Not all models have the app installed on the TV, but go to the list of all apps and tell me if you see it there please?
This is where you see all apps available to the TV such as BBC and netflix ect.
ok, then you will need to get the Amazon Fire Stick which you can purchase from my link below for £34.99
You connect it to one of the HDMI ports on the TV and you can then view Amazon Prime via this
If you would like any additional information or assistance, please do not hesitate to let me know.
And if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.