Be sure that both your Mac and your iPhone/iPod touch are connected to the same wifi-network.
If you need assistance configuring your wifi network you can read this comprehensive online guide at
http://www.goodiware.com/gr-man-tr-wifi-create.html
from the creators of the iPhone GoodReader app.
Once BabiBooks Synch will detect your device, an iPhone icon will appear in the top-right corner of the application window and you will be able to start to backup and restore your BabiBooks' library.
Be sure to be in the Backup/Restore screen of BabiBooks on your iDevice, otherwise the connection won't happen.
I you need further assistance you can contact me at stefano@babisoft.com.