In the Environments tab you will be able to choose the environment you want to use.
Some environments are predefined for certain avatars(e.g. The Lava Pits work best with The Lava Baron).
Gallery this is where you pick your background by selecting the thumbnail and double clicking or clicking
Each background has a title(background name), listed on the blue bar, and a thumbnail.
To load a background, simply doubleclick its thumbnail or click the thumbnail once and then click the Load
The search bar above the background names bar allows you to search through the backgrounds by inputting
one or more characters. If the string is present in the background name(s), the background name(s) will
appear on the left side of the title bar, in a scrollable menu.
In addition to this, the thumbnails will be filtered to match the search result. To cancel the search (unfilter
results), delete the string in the search bar.
Customization and Postprocessing are mainly aimed at advanced users, allowing them to adjust things
like Lighting, Shadows, Ambient, Fog, Tonemapping, Bloom, Depth of Field and others. only available in
the Advanced Interface
Control + Left Mouse Click will allow you to rotate the background, if the background being used
at that time is a full 360 degree environment cube, not just a 2d backdrop.