Your best bet due to your level of mechanical knowledge is to take it to a machine shop and if you are lucky, ask them to allow you to watch how they repair your engine. Also, try to find someone locally who is mechanically inclinded and can teach you how to maintain the engines.
I personally prefer time-sert over helicoils. ++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair,
You can google/youtube timesert and find videos how to use these thread repair products.
Good luck, there is only so much learning you can get from a forum.