That is strange. The iPad should pop up a "1" in Configurator next to the Prepare tab. Are you able to see the iPad in iTunes on your Mac when its plugged in? Try different USB ports in case one of your ports is bad on your Mac. It could be a bad cable too… If you have an extra iPad cable try swapping out the cable.
After checking connectivity, I would reboot/reset the iPad: press and hold the Sleep/Wake button and the Home button at the same time for at least 10 seconds, until the Apple logo appears. Once it boots back up, plug the iPad back in to your Mac and see if iTunes sees it.
If that doesn't work (and if you're okay deleting all of the data on your iPad), wipe the device by going to Settings -> General -> Reset -> Erase All Content and Settings. When it restarts, go through the setup windows until you get to the Home screen. Try plugging the iPad in to your Mac again.
From your post, it sounds like you tried holding down the button on the iPad until the iTunes logo appeared. If you see the iTunes logo on the iPad, you will need to use iTunes on the Mac to set up the iPad before you can use Apple Configurator. Just get past all of the setup windows on the iPad until you get to the Home screen. Then you should be able to see the iPad in Apple Configurator when plugged in via USB.
Once you see a "1" next to the Prepare tab, you can add the profile by placing a checkmark next to the profile and clicking the Prepare button.
Hope this helps!
~Joe