confused course difference download e-mail edit email includes link message order page payment product products setting thank-you thank-you-email

I am still confused about the "e-mail message" that gets sent with download link and the "thank-you message" that gets sent after payment. As far as I can see with my products, there is only one message sent and that one includes the link and of course it comes after payment. What is the difference between the two?
I'd like to add a message but I'm not sure which setting to edit...??

There is only one "email message" that goes out for a product in the order. That email is the thank you email.

The other thing you are talking about is thank you "page".