Yeeah, super easy actually I made that batch on the 8/12

Start with some good organic cabbage, everything has to be super clean first of all I use water and vinegar also boil the jars sometimes, sometimes I don't, glass jar and distilled water if possible. that way chances of ruining it go down.
and then just chop the cabbage down and then massage it with some salt. depending on the ammount of cabbage I would use around 2 oz per lb of cabbage maybe, sometimes less.
Massage it good and smash it let it rest, it will create juice then just put all on the jar, Save the outher leaves and wash them good to put inside the jar and press the cabbage down you want to keep it cover with liquid if it didn't drop enough liquid just add water, Distilled water is preferred because is cleaner but I just use tap water, sometimes I boil it and cool it down.

I add caraway seeds it gives it a good flavor, but I have done some garlic, or jalapeno, one time I made a beet one color was super nice ahahah

Just play with it luckily cabbage isn't that expensive