Kimchi, in broad terms, being basically similar in concept to european antipasto/sauerkraut, but used as more bulk servings. You want to make wide/long slices as will fit in your jars, not shredded or chopped.
--any thin-sliced firm vegetables you like, typically cabbage based, but added carrot, beet, daikon, leek, apple, cucumber, citrus, onion, horseradish, etc is fine. Almost anything you would pickle, you can kimchi.
--very thin sliced fresh ginger, or dried ground ginger can be ok too
--salt or flavored brine (and/or sugar too) and/or vinegar in proportion to how pickle-ish you want to make it (i've seen pure water and 1/2-vinegar versions)
--hot pepper powders/sauces (store bought vietnamese hot red pepper paste/sauce with seeds is fine)
--garlic, sesame, coriander, turmeric, or other spices/oils to taste. You could even crush a vitamin C tablet in there
--option: soy, fish, or worchestershire sauces if you want to funky it up a bit more
--option: beef, fish, shrimp, or shellfish stock or brine; or bits/slices can be added for protein
--option: you can use some sake or white wine for some/all of the liquid if you like
--You stuff the sliced raw veggies fairly tight in jar(s), add the liquid to cover, then keep it in the fridge or bury it in the back yard (traditional) for a couple or a few weeks until it is pliable but not mushy. Burying was used before modern refrigerators, and obviously brings in some risks/techniques for not killing yourself with botulism and other microbes. The fridge is fine, although I've known some people who swore by burying, and their kimchi was awesome.
--Don't be skimpy on the spices! This is supposed to clear your respiratory system a bit.
--There may be some natural fermentation going on in the pickling process. Cabbage and fruits can both support this.
--If you're paying more than a few dollars/euros for a quart of kimchi, you might as well make it. It's cheap stuff but really helps keep up the metabolism in cold weather. Make it spicy! Kimchi and other spicy foods can help reduce your susceptibility to viruses.
--Hot peppers are from Central America, so they weren't included in kimchi recipes until the last few centuries. Chili peppers have conquered most of the world already, being some of the most aggressively colonial species in the world. Few human cultures have been able to resist their relentless assault of flavor, nutrition, and general stimulation.
--Kimchi is a broad class of pickled/fermented/preserved foods. There is no single recipe. It is as variable as the availabilities and preferences of the areas it is made, using whatever local/family ingredients are favored. Do whatever you want/like with the variations. As long as there are enough preservative ingredients included to avoid rotting or contamination before you eat it, it's a go.
In case you didn't realize it, I DO have a sense of humor. How about you?
"I will not fear. Fear is the mind-killer... I will face my fear. I will let it pass over and through me, and when it has gone, only I will remain." --The Bene Gesserit
"Time is a spiral. Space is a curve. I know you get dizzy, but try not to lose your nerve." -- Neil Peart
"I'm not in the ship. I am the ship." -- River Tam
"The truth is simple. It's the lies that get complicated." -- me
"No matter where you go, there you are." --Buckaroo Banzai