Instructions
Insert the "Call of Duty: Black Ops" game disc into your PS3 console and select "Multiplayer" from the main menu.
Choose the "Store" option from the Multiplayer menu. A new dialog box will open up with three tabs: "Map Packs," "Avatars" and "Themes."
Open the "Map Packs" tab and select the "First Strike: Pack 1" option in the list. Follow the onscreen prompts to purchase and download it.
Go back to the main menu after it has downloaded to your PS3 console and select "Zombies."
Choose your mode of play ("Online," "Split Screen" or "Solo") and select "Ascension" as your map to begin playing it.