A background is a scene on the stage. You can perform any operations on it through programming.
Add a Background
(1) Click + on the Background tab.
(2) Search for the background you want in the background library, choose it, and click OK.
(3) If the background library does not contain the background you want, you can paint your own one or upload one. In the dialog box that appears, click Upload or Paint on the top.
Add Costumes and Sounds for a Background
Similar to sprites, you can set costumes and sounds for a background. For the setting steps, refer to the steps for adding sounds and costumes for a sprite.
Note that the stage displays only one background at a time. If other backgrounds are added, they are presented as costumes.