I'm working from this book, heaps of different recipes in it.

It's basically a medium cabbage and a tablespoon of salt. Chop the cabbage finely, add the salt and knead/crush in a bowl until you get lots of liquid. Then into a jar, weighing the cabbage down under the liquid, for 5-7 days at room temp.

One change is I would let the salted cabbage sit for an hour or so to let the salt work before I crushed.