You download either a generic or pre-set for a game package from the ENB website. After you get that you find the enbinjector.ini file and add the ffxiv.exe as a process.

From that point on it's just start up the ENB injector and then FFXIV.exe and you're good to go. That is assuming you already have a pre-set config for FFXIV. At the moment there isn't any on the site or available via reddit so far that I have found. You can try playing around with say the Skyrim package then editing the config .ini, but it's a tedious process. Not to mention when you load the game up the first time with said config your character looks like they're going to explode with light in every direction.

At best if you don't want to get really involved wait for Serj to post his .ini file or explain which setting package he used and go from there. It's nice because you can use SweetFX concurrently with ENB, although have to be running a decent enough machine.