After you have set up your Mac for MediaTransfer, all you need to do is enter your Username, Password and select your Mac from the list of Macs in the settings screen...
To get to the settings screen, run MediaTransfer and then swipe your finger from the bottom of the screen to the top of the screen.
Since you are using a Mac, you can select your Mac from the list of Macs that automatically comes up.
Enter your username and password you chose for your FTP server and then click the Done button. MediaTransfer should start transferring...
Note: If you see an error on the main screen stating "No access to camera roll granted", please check out the video to the right titled "Granting access to Camera Roll" to fix the error.