Press and hold the side button on your Apple Watch until the Apple logo appears
Wait for the Apple Watch to start
If prompted, select your language on the watch
Bring your iPhone near the watch and follow the on-screen setup prompts
On your iPhone, open the Apple Watch app if needed and tap Start Pairing
Confirm the pairing code on the iPhone and watch
Sign in with your Apple ID when prompted
Keep the watch on its charger during setup if asked
If the watch is off and won’t turn on, press and hold the side button and charge it for at least 30 minutes, then try again