1. Open the Settings window by clicking the Start menu and selecting the gear icon from the left-side column.
2. Select Personalization from the list of available menu options.
3. Choose the option for Background from the left-side column.
4. Click the drop-down menu next to Background to select the type of background you wish to use: Picture, Slideshow, or Solid Color.
5. For Picture or Slideshow backgrounds, click the Browse button to find the image file you’d like to set as your background.
6. For Solid Color backgrounds, click the drop-down menu to select the color you want.
7. To adjust other settings such as how often your background will change (for Slideshow backgrounds) and whether or not your background will fit the screen, click the Advanced Slide Show Settings link.
8. When you are finished customizing your background, click the Save Changes button.