I've done it a few times and it's not difficult, but it is a lot of work (chopping, soaking, mixing, packing) and it can take anywhere from a day to a month or so before your kimchi is ready to eat, depending on what kind you make. Cabbage kimchi takes me several hours to prepare and then at least two weeks to age (4-6 weeks is better) before it's ready to eat. Green onion kimchi takes about five minutes to chop, twenty minutes to sit, another five minutes to season and pack, and it's ready to eat the next day.
There are a lot of recipes online so you can pick one that seems to be to your taste. I make mine with: napa cabbage (though I've used shredded green cabbage and that worked all right), shredded carrot, shredded apple, green onion, Korean red pepper flakes, mushroom broth (dried mushrooms and salt), fish sauce, garlic, and ginger. I made one with miso paste and mushroom broth for my mom since she's allergic to fish sauce, and it tasted pretty good.
Tips: 1) Buy a pair of rubber dishwashing gloves. Keep them as your kimchi gloves. It will keep your hands clean because . . .
2) It's a lot easier to mix the vegetables and seasoning paste with your hands than with a spoon. You can squish everything together and make sure the paste is well-distributed.
3) Have a lot of jars on hand before you start. I use pint jam jars and sterilize them like I would for making jam before I make cabbage kimchi, but make sure the jars have cooled before you pack the vegetables into them. I have a small glass jar that holds about a cup for green onion kimchi. I use a 1 kg glass honey jar for diced radish kimchi. I've made kimchi successfully in used plastic yogurt containers as well. As long as you can pack it full and seal it, it should work.
4) Pack the jars full. You can leave a little bit of space at the top, but not much. If you find that your last jar won't be filled, you can either move the contents to a smaller jar or press a layer of plastic wrap on top of the vegetables to limit their exposure to air.
5) Always put the filled jars on a rimmed baking sheet or something like that, because the juices will bubble up and get all over everything.