But yeah, easiest thing is to make a 3%'ish brine solution (about a 3/4 Tbsp salt per cup water). Sliced veg packed reasonably tight into glass jar, cover with brine and keep submerged with a thick slice of cabbage or onion. Most of my ferments now are onion, chilli, maybe some mango / onion / ginger etc. kept for about a week or two at room temp then into the fridge. They turn a cool purple/pink from the cabbage on top.
I cba with traditional kimchi. My dad makes a version that's more like saurkraut. Finely chopped cabbage and other veg packed and covered with brine and fermented for a few weeks. No special spices or chinese cabbages required.