Add instruction for iOS clock sync

Add reference to phyphox

userguide/watch.md

@@ -4,6 +4,17 @@ weight: 50
 ---
 
 ## Setting the time and date
+### Using an iOS device
+As iOS offers a time service via bluetooth, you can use a bluetooth connection to your iOS device to sync the time to the watch.
+1. Enable bluetooth on your watch
+2. Connect to the watch using your iOS device
 ## Watch face options
 ## Accuracy
 ## Energy consumption
+## Interact with your watch
+### on iOS using phyphox
+1. Disconnect your iOS device from the watch
+2. Download phyphox to your iOS device: https://itunes.apple.com/us/app/phyphox/id1127319693?l=de&ls=1&mt=8
+3. Go to the following url on your PC and scan the QR Codoe via the phyphox app  https://phyphox.org/wiki/index.php/Card10
+4. Connect to the watch via the dialog of phyphox
+5. Read supported functions (currently only ther light sensor)