Pairing apple watch to my iphone

To turn on your Apple Watch, press and hold the side button until you see the Apple logo. Bring your iPhone near your Apple Watch, wait for the Apple Watch pairing screen to appear on your iPhone, then tap Continue. Or open the Apple Watch app on your iPhone, then tap Pair New Watch.

Set up and pair your Apple Watch with iPhone - Apple Support

With new Apple ID? --> Set up your Apple Watch - Apple Support