There are two ways to backup the database.
1. To backup all the plays currently in the database go to the File menu and choose Backup playbook.
2. Every twenty-fifth time the program starts you will be asked to make a backup, which is highly recommended.
To start a backup of your current plays press the OK button.
To skip a backup press the Cancel button.
Checking a check box can disable the automated backup question, this is not recommended.
After pressing Ok you can choose the file destination in a save file dialog.
Although backups seem to be time consuming, you would not be the first to have an accident, like a power failure, resulting in a corrupted database and loss of work.
The steps on how to recover a database are described here.