Hello confiance67,
Welcome to the Apple Support Communities! It seems that you're looking for information on how you can pair your Apple Watch with your iPhone.
Checkout the troubleshooting steps from this article to begin: Set up and pair your Apple Watch with iPhone.
If your Apple Watch will not power on, you'll want to follow the steps in this article: If your Apple Watch won't charge or it won't turn on.
If the Apple Watch will power on, but will not pair let us know the following:
1 - What is the iOS version number on your iPhone?
2 - Which iPhone do you have?
3 - Do you recall which Apple Watch model this is?
4 - Have you paired your Apple Watch with this iPhone before? If you haven't, have you paired it with any iPhone before?
All the best.