Much has been written here regarding spark plugs. Try the search feature for all the reading you want on the subject. Generally speaking most members will agree that the kit supplied Chinese plugs can be a source of trouble. Most of us replace it with the NGK brand, specifically the B6HS plug. There is also a lot of disagreement about the plug wire. A wire with a metal conductor, preferably copper is considered by many to be superior to the resistance wire sold by most auto parts stores today. There are a couple of resistance wires that will conduct electricity as well, maybe even better than the standard metallic core wire but you'll need to do some reading on that and make your own decision. As for the plug boot, the plastic kit one is not the best choice and should be replaced with a good automotive type that doesn't require removal of the threaded cap on the top of the plug and has more contact surface inside. The plug wire simply screws into the CDI (ignition module) and the kit boot. Unscrew it like you would anything. Lefty-loosie, righty-tighty. I'm one who solders my wire at the plug boot instead of relying on a crimp-on connection. Hope this helps a little.
Tom