Whether you are making Spot Gloss, Raised Spot Gloss, or Gold Foil Cards two files are required.
One for ink which we call the Design Layer. This is a standard file that you would use to print other products, and has the same requirements.
The second file tells us where to put the Tailored Element you chose. This will be black and white, like a chess board. The black in the file is where the Element will be applied.
Design Layer (Ink)
Element Layer (Foil or Spot Gloss)
Here's an example for Gold Foil: