First, check your junk mail folder. Halterix PT+ invitation emails sometimes end up there. If you still can't find it, tap the request a link from your clinic link from the PT+ sign in page. Be sure to select your clinic from the drop down list.
If you already have exercises assigned to you in PT+, there's another way to download to your smart watch: Tap Record on any exercise. If you're watch is connected to your phone, PT+ will attempt to push the application to your watch, and you'll see a notification to download PT+ on your Google OS watch's main screen.
PT+ relies on data collected from your Wear OS device to evaluate your exercises. We want to be sure to collect data from your complete exercise routine, so we make sure your watch has enough juice left to record a whole set of exercises.