All you need is a cabbage and 2-3 tbsp of salt.
Simply chop up your cabbage and discard any thick stalks. Rub in the salt and press under a weighted plate for an hour. You’ll see water starting to come out of the cabbage which is exactly what you want.
Tightly pack the cabbage into jars and pour the leftover liquid on top. You want the cabbage to be covered by liquid. Leave at room temperature overnight then refrigerate.
I leave my Sauerkraut at least a month in the fridge before eating it but open it once a week and give it a taste. You can then see how fermented you like it.
Want ideas for what to do with it? Check out Peter’s pierogi which are filled with Sauerkraut, mushroom and potato – https://www.youtube.com/watch?v=wWNwWZJMPjA&t=58s