I don’t have the app and it won’t even let me get it

Hi

Check that you have a compatible model of iPhone, which is required in order to pair, set up and manage Apple Watch:

Set up your Apple Watch - Apple Support

If you have previously removed the Watch app from your iPhone, then follow the instructions here to add it back:

Delete built-in Apple apps on your iOS 11 device or Apple Watch - Apple Support

Maybe you'd like to tell us what app you're referring to... just for clarity.