Hello Hankdoc,
It sounds as though you’re having issues find the TV app on your iPhone, and seeking to download movies to your device to watch when not connected to cellular data or Wi-Fi. Apple Support Communities is a great place for help!
It sounds like the TV application is installed on your device, but not showing on the Home Screen. You can add an application back to your Home Screen from the App Library. To do so, swipe from right to left across the Home Screen on your iPhone to access the App Library, locate the TV application, then press and hold on the application icon. When you see the Add to Home Screen option please tap it. This will bring the app back to the Home Screen.
You can find more information about organizing your Home Screen and removing apps from the Home Screen in the following articles.
Remove apps from iPhone
Organize the Home Screen and App Library on your iPhone
In reference to downloading movies you can find those steps in the articles below.
Redownload TV shows and movies that you purchased
Download and stream shows and movies from Apple TV+ and Apple TV channels
Take care!