Turn on “Ring through the day,” pick how often (15–120 minutes) and how long each little pause lasts. Your Apple Watch then taps your wrist on schedule — close your eyes for a moment, breathe, and come back. You don't need to keep the app open.
Change the settings on your iPhone and they sync to your Apple Watch automatically. The watch is the one that rings, so it works even when your phone isn't nearby.
Make sure Kyros Mind is installed on the Apple Watch (Watch app → scroll to the app → Install), that notifications are allowed for it, and that the bell is switched on. Quiet hours will keep it silent outside the window you set.
Switch “Ring through the day” off on either device — it goes quiet everywhere.