Please see also here for an updated baseline guide for systems newer than 2.3: https://nguvu.org/pfsense/pfsense-baseline-setup/
How To Set Up pfSense 2.3 for AirVPN
Guide is updated to pfSense Version 2.3
This guide will work on 2 or more interfaces.
Please inform me of any and all errors found!
Feedback is appreciated! Please rate this post or leave a comment to share if this worked for you!