You’ll find setup assistants on both your iPhone and your Apple Watch that will walk you through the process— it takes about three steps. Start by updating your iPhone with the latest iOS. But first, make sure you have an Apple Watch Series 4 or later with watchOS 10, and an iPhone XS or later running iOS 17 or later.
Put your Apple Watch on your wrist and turn it on. Hold your iPhone near your watch.
Follow the instructions on your iPhone to set up your Apple Watch.
Activate your cell service.
Keep your devices close while they’re syncing.