Find the main installation folder of the game.
JDownloader will decrypt the file and add the download links to the link grabber list.
Start the downloads to acquire the actual content. Unlock DLC.zip
If Unlock DLC.zip is a zip file containing files meant to be placed into a game directory:
Copy the extracted files and paste them into the game directory, overwriting existing files if asked. Find the main installation folder of the game
To make sure I'm giving you the right steps, could you let me know: Is it a or a .dlc file extension? Which game is this for?
Scenario 1: A Compressed Archive ( .zip containing game files) Unlock DLC.zip
Knowing this will help me guide you to the specific files or settings you need to change.