The timer countdown begins as soon as you move the line. It will continue to countdown - even if you stop moving the lure (for example if you need to tie on another lure, etc.)
Once it counts down to zero - the "Play Session Has Ended" message window pops up. Click Okay to begin a new session 👍
To manually start a new play session - click the back arrow on the upper left side of the app
Then select the device again