Not hard at all, I just laid out a bunch of masking tape in the general area where the lights would go, measured and marked my holes on the tape, pull the visors, overhead console, and OH SHIT handles, so I could drop the headliner a couple inches, then wrapped the drill bit with tape so it could only drill through the roof itself and would stop before it continued to the headliner
. Not bad at all. The first set I did took about 2 hours (white truck), 2nd set took about a 1.5 hours (had to go find new screws because the RECON ones were shit, burgundy truck), and the 3rd set took about 45 minutes (black truck).