Pretty straight forward. Take apart under your dash, cut the black/yellow wire coming from your ignition, wire it up to the switch.
I realized that in the video I say "yellow and black wire" while holding the yellow/white wire. You want to cut/tap into the black with yellow stripe. With these civics there are two wires that are for your ignition. One is "start" and the other is "start AND run." This one is for start and run. Make sure you use wire big enough to pass along enough current or you may have problems. I believe I used 10 or 12 gauge. If you have issues, work your way backwards and you should find where you went wrong.
Honda Civic Ignition Killswitch Install