How do I open it in Protools after installing? It's not appearing in the plug-in menu.
Based on my experience, I know that for these VST plug-ins there should also be a readme file where you can see the installation procedure. I've checked the website and these are the compatible applications available for this VST:
Pro Tools - 10.3.8 or later (AAX)
Cubase - 6.0.7 or later (VST3)
Nuendo - 5.5.6 or later (VST3)
Ableton Live - 9.1.8 or later (VST2)
Studio One - 2.0.4 or later (VST2 and VST3)
You can check for additional information on the following website: http://www.antarestech.com/support/host-daw-compatibility.php#auto-tune-efx3