From the main menu, select Extras.
In the Extras menu, select Downloadable Content.
Scroll through the menu to find the specific content you are looking for.
Follow the on-screen prompts to download your content.
Remember, if you have purchased the Season Pass for Mortal Kombat on Xbox 360, you will need to access the downloadable content following the steps above. Or you will end up paying the full price to Microsoft if you access it via Xbox Live Marketplace.