I’ll be honest, its a pain in the booty. It will take a weekend to do it right. But if you take the time and do it right, it will be worth it. Take the time to thoroughly clean the undercarriage of the vehicle.
POR-15 makes a great, three step kit that includes a cleaner, etching primer, and the actual POR-15 coating. They also make a top coat that hardens the sealant even more. It’s also a good idea to coat the inside of the frame rails. There are a few coatings that come in a spray can with a long nozzle that can be inserted into the frame holes.
Also, use the gloss black, not the flat black. Mud and grime seem to not stick as easily to the glossy surface.