Hello @DerekP41 ,
If the lead ad was made in your Constant Contact account, then newly subscribed contacts would be added to the associated list. I'd recommend checking these relevant articles, available via the Help tab in your account, for more info on how the lead ads work and how to manage the subscribers:
Create a lead ad for Facebook and Instagram
View the results of a Facebook Lead Ad
View the sign-ups generated through your Facebook Lead Ad
... View more