Not a bad demo for you to get started. But a couple of comments on the video.
1. I like to lay down a layer or two of masking tape where the hole is going to be so that when I drill, the bit does not chew up the paint around the hole. I want the gasket at the base of the antenna to rest on paint, not bare metal. It's an invitation to rust, and rust can interfere with antenna function.
2. Antennas work best with a ground plane of at least 15-20" in all directions. Placing the antenna at the edge of the truck roof eliminates about 45% of the ground plane. Ideally, the antenna should be in the center of the roof. If there is a ceiling light in the vehicle, you can drop it, pull the headliner down a bit and then drill just a few inches forward or rearward of the light. Feed the cable across the roof behind the headliner and drop it along one of the pillars.
3. I live in way upstate New York. They use a lot of salt on the roads in winter here, and it accelerates corrosion and can interfere with all kinds of electrical things in cars and trucks. For that reason, I coat electrical contacts with a light layer of dielectric grease. That NMO is a lot of bare metal and I would protect it well.
4. When you route the antenna cable down to the radio, be sure to protect it from any sharp edges of metal or plastic. I use rubber grommets when passing through a metal or plastic bulkhead. 1/4" loom is good for general protection. If the cable has to go outside the vehicle passenger compartment for any reason, make sure it is in loom out there. Same for your power cables out to the battery and ground and the ignition sense line. Protect them well.