Hello & Welcome to Just Answer,
Sorry to hear of any issue you may be having with your new device.
I have a link to a video that shows how this is done, BUT since you have the application already installed on your phone, you can ignore the "create an account" part at the beginning of the video, and go straight to the "Connect a Device" screen in the app.
Click Here for video --> https://www.youtube.com/watch?v=Mi3ADq4GwQE
NOTE: When connecting a NEW (or different) device, there MAY be some other setup to be done, so don't be surprised if that happens.
If this helps and has answered your question(s), please take a moment to rate MY service level (Excellent is my goal) so that I get credit for my time helping you with this question.
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Thanks, ***** *****