how do I set up my 13 year olds new phone on my apple Id

Apple ID shouldn't be shared!

Make sure each of you have your own Apple ID.

Read here for a child under 13 => Create an Apple ID for your child - Apple Support

Yes. Every family member needs their own Apple ID.

This site will walk you through setting up an Apple ID, adding restrictions, family sharing, etc.

https://support.apple.com/families-and-kids