Hi demetris212,
For help with signing in to your Apple ID, have you checked to see if you're already signed in from the Settings on your paired iPhone? If so, the sign in to your Apple Watch should be automatic. The steps below found in the article here can assist. Sign in with your Apple ID
"Sign in on your iPhone, iPad, or iPod touch
- Open the Settings app.
- Tap Sign in to your [device].
- Enter your Apple ID and password.
- If prompted, enter the six-digit verification code sent to your trusted device or phone number and complete sign in.
If you're already signed in to iCloud on the iPhone paired with your Apple Watch, you will automatically be signed in to that Apple ID. Learn more about how to set up and sign in to your Apple Watch. "
Should you continue to have an issue, check out and complete the steps here: Set up your Apple Watch
If the issue remains, reach out to Apple Support directly to further assist.
Contact Apple Support
Contact Apple for Support and Service
Cheers.