Insert record from form and then show Auto Number of new record in form

Insert record from form and then show Auto Number of new record in form

Hello,

I want to create a new record (Stock1) On Success ( form form Orders)  (I know how to do this), then return the Auto Number of the new record created (Stock1) and record it in the form (Orders).

This does not have to be On Success, it could be On User Input from another field.

How do I do this?