To create a backup, simply click on "Devices" on the toolbar, and click on "Backup...".
iBackup Extractor will check if your device is connected, and request you to do so if you haven't already.
Once iBackup Extractor has found your iOS device, click on "Continue" to create a backup.
The backup of your iOS device will now be stored on your computer and listed in the drop-down menu in iBackup Extractor. Select this backup from the dropdown menu to explore the backup's content or extract files from the backup.