Tap the centre knob to lock and unlock 4 tap actions at the 12, 3, 6 and 9 oclock positions for the calendar, Google Fit or Samsung Health, messages and timer apps. The rotating dials show the watch battery level, date, month, day and clock seconds. Tap actions were tested on a Samsung Galaxy smartwatch and may not work with other smartwatches. If the tap action for timer does not work because there is no timer app in your watch, please try installing the free timer app from Samsung Electronics. The tap action should work once the app is in your watch. The app can be downloaded from Galaxy Store under the watch apps category.