The Xbox 360 version Call of Duty: Ghosts comes with two discs. Follow the steps below to play either Campaign or Multiplayer.

Single Player/Campaign
To play the Call of Duty: Ghosts Campaign, you will first need to install the contents of Disc 2. You will need approximately 3 GB of free space to install Disc #2.
  1. Load Disc 2 — Install Disc into your console and launch Call of Duty: Ghosts.
  2. Select Install Campaign.
  3. Select a Storage Device and begin the installation.
  4. Once the installation of Disc 2 is complete, replace it with Disc 1 — Play Disc and launch Call of Duty: Ghosts.
  5. Select Campaign.
As long as the contents of Disc 2 remain on your console, you will only need to launch Disc 1 to play Call of Duty: Ghosts Single Player/Campaign.

Multiplayer
To play Call of Duty: Ghosts Multiplayer, simply load Disc 1 — Play Disc into your console and launch the game. From the main menu, select Multiplayer.