Pairing Apple Watch after changing iPhone and losing iCloud credentials

I lost my phone and forgot iCloud, restored iCloud on another phone, but the watch asks to disconnect the pair from the old phone or enter an account when setting them up, this data is not available, all there are documents from the watch, mail and phone number when creating iCloud, how to connect the watch?

[Re-Titled by Moderator]

Original Title: I forgot the login and password from the watch and changed the phone, the watch asks to specify an account when setting it up