There are 2 possibilities to copy backup files to and from a computer:
- Use a Dropbox upload
- Use iTunes Filesharing
Dropbox
To upload a backup to dropbox, slide the backup entry in Stage Traxx to the left and select the Share option.
iTunes Filesharing
Open iTunes on your computer and connect your iPad. Now open the iPad in iTunes and select the Apps screen as shown in this picuture:

When you scroll down the screen, you will see a section called File Sharing. When you select Stage Traxx, you will see a list of all files accessible by Stage Traxx. Backups have the suffix .stb. You can drag and drop files to and from the iTunes window.