Note: Biteable Lite is the version of Biteable we made in 2015. After receiving much feedback through the years, we've built Biteable Pro, a brand new editor that offers more in terms of flexibility. Biteable Lite is now only accessible to older users, and it will retire in 2021. For information about how to make a video with Biteable Pro, check out this section of the FAQs.
In Biteable Lite, to change which scene you're using just click on the scene in the timeline at the bottom of your edit page. From there click on the white arrow and choose Switch Scene. This will allow you to choose a new scene in place of the one you're working on.
If you're using Biteable Pro, to change your background you'd just need to click on the video box and click Replace Background!
For more things you can do with your Biteable Pro backgrounds, head over to this article!