NxFilter Tutorial
Install NxFilter on pfSense
Rob Asher wrote a script installing NxFilter on pfSense.

Using script
Rob Asher wrote a script installing NxFilter and its dependencies on pfSense. You can easily install NxFilter on your pfSense or Netgate box. There is a Github page for his install script:

- Rob Asher's Github page for NxFilter install script on pfSense