On the Receive screen it will show your address. Just copy and paste that into your nostr profile where it says Lightning, LN, or bitcoin tips. (The label on the client.)
https://image.nostr.build/b3de719a07f7e80ebe5f8c5ef32fbe49a539250ecd468f1fd1694f768202ba94.jpg 

 I think I've finally got it settled. Still getting used to the fact that there are so many different clients here.