Connection process is pretty simple, click on the t-mobile link. Put your phone number in and it says "Verifying" and that's it. I don't know if it checks against the SIM or anything. I use a dual sim iPhone 14 with one being AT&T the other is T-Mobile. AT&T is my data side, T-Mobile is voice.
The connection won't handle HD, but 360p and 480p were just fine. I prefer to stream a Seattle radio station I like, or listen to different pod casts on Youtube and it works fine.