Forwarding calls from your iphone to your apple watch

Since your iphone and apple watch 3 have different phone numbers, what happens if you only publish your iphone number? Can you have calls to your iphone forwarded to your apple watch 3, if for example, your iphone is turned off? Or if your iphone does not answer (e.g., you left it home)?

And similarly, if people call your apple watch 3 phone number directly, will it answer without the help of your nearby iphone?

And if people call your apple watch, but cellular on the watch is turned off, will the call be redirected to your iphone number?

Basically, how do the two different phone numbers interact?

Thanks?