Most everything you want to know about Blink regarding how to use it, how to set it up, how to change it has already been given to Blink owners via the online owner’s manuals.
These are available via the Blink support website. Use the search function to find topics that interest you. Type in different words to find different versions of the same subject matter. The example below shows you how to add a 2nd mobile device. Get the 2nd one running and simply delete the mobile app off your 1st device to “start fresh”.