What do I do to back it up on a iPad
Nothing
Question marked as
Natively supported backup methods for your iPad are to iCloud, or using Finder (current versions of MacOS) or iTunes (Windows PC and older versions of MacOS). These are described here:
How to back up your iPhone, iPad, and iPod touch - Apple Support
If you are trying to backup something specific that cannot be accomplished using these methods, you’ll need to provide more information about what you are attempting to achieve.