Site Links can only be imported from an existing ad that has site links configured. Creating Site Links from scratch is currently not supported.
Click on the “Launch Settings” button in the left-hand column, then scroll to the bottom to access the Setup site links.
Search by ad name to select an existing Ad from your Meta ad account to import site link settings, and click 'Save'.
In the left-hand menu, click on Creative Enhancements. Toggle on Add Site Links to activate the Site Links setup.
