Checked bottom cowl fitting with FAB in place, determined the front of the FAB needs trimming ~ 2".
Proceeded with locating the filter retainer clips and nut plates. Match driller the FAB top plate, and filter retainer clips using the nut plate as a guide for the AN3 rivets.
The retainer clips ensure the filter stays in place sandwiched between the top plate and filter box, so we don't have any FOD particles (silicate, dirt, etc.), that might want to take the path of least resistance past the filter, into the engine.