Please do backups regularly.
An easy way is to use iFunBox.
Here is how to backup and copy to another iPad with iFunBox
Here is how to backup and copy to another iPad with iMazing.
Before Catalina, the fastest and most reliable way is to use iTunes.https://diystompboxes.com/unrealbook/manual/how-to-make-a-manual-backup-of-unrealbook-files-with-itunes-12/
This method will backup only the unrealBook music files and works well.
The following methods require you to restore the entire iPad if you need to recover the backup:
Make a complete backup of your iPad via iTunes.https://diystompboxes.com/unrealbook/manual/how-to-make-a-manual-backup-of-unrealbook-files-with-itunes-12/
However, if you are running Catalina, this is no longer easy or possible to do.
Therefore, use iCloud backup:
Press the + button in the set list toolbar.
Choose Share… Set List And All Files.
Choose whether you want to include annotations (drawings).
When the share window comes up, choose Copy to Dropbox
In the Dropbox app, confirm the save.
The zip file will be saved into your Dropbox folder.
Save the entire set list as a single PDF
You can save your set list as a single PDF with the annotations intact. Note that this function is dependent on the amount of RAM that your iPad has. This function may fail with super large set lists.
Load a set list.
Load a set list using the set list popup in the center of the set list toolbar.
Use the + button in the set list toolbar to save the current set list to a single PDF file.
Choose Set List to PDF.
Name the PDF file that will be created from the set list
Note that any bookmarks or indexes that do not have a number of pages defined will be saved as a single page.
Choose this to print a PDF to a compatible iPad printer.
If you are connected to another iPad using Bluetooth, the current set list file that is selected can be sent to the other iPad. Only available when a Bluetooth connection has been made.
If you are connected to another iPad using Bluetooth, the current file that is shown can be sent to the other iPad. Only available when a Bluetooth connection has been made.