Alert sounds on Apple Watch
It is not currently possible to use a custom alert sound on the Apple Watch. You can still pick any sound you want, but unless you pick “None” the default alert sound will play on your watch. The selected sound will sync to your other devices though.
Alert sound when phone is silent
It is not possible for 3rd party apps to play notification sounds when the phone is on silent. It will display the notification.
You can register and login to Tidur Cloud Sync by enabling cloud sync in settings. The login screen will be presented automatically.
To login on your watch, login first on your phone and close the app. Then launch the Tidur on your watch, force touch and select sync. A screen telling you to launch Tidur on your phone should appear. Follow the instruction and wait until the screen disappears.
You can use the tidur:// URL scheme to manage your timers.