First, Shred or cut the the cabbage. I like to do this with a knife, but you could use the shredder function on your food processor.
Put the shredded cabbage in a large glass or steel bowl.
Next, sprinkle the salt over the cut cabbage. Let the salt sit on the cabbage for about 20 minutes or so.
After the salt has soaked into the cabbage, use your hands to mix it and "work" it into the cabbage. You should be seeing the liquid in the bottom of the bowl grow. Work it for about 5 or 10 minutes.
Now add the spices if you are going to. I like to use 2 teaspoons to one tablspoon of caraway seeds.
Finally, add the cabbage and salt mixture to your mason jars. Pour the salty cabbage water over the top, dividing it equally between your jars. Add water to cover the cabbage, leaving about an inch or inch and a half from the top of the jar to allow for expansion during fermentation.
Let it sit out of direct sunlight for at least 3 days and up to 2 weeks.