How a digital product gets made and sold
Write the result before the outline
Say what the buyer can do when they finish. If that sentence is vague, the product will be vague.
Sell a finished slice
A short template people can use tomorrow is a product. A promise of a future library is not.
The checkout is part of the product
Someone must be able to pay and receive the file without emailing you. Test that path yourself before you tell anyone the link.