To shred veggies like cabbage, you have 2 choices. Pull off a few outer leaves; roll them into cylinders and thinly slice crosswise to create long threads. You may also cut the vegetable in half and lay the flat side on the board and slice crosswise into threads. This is more challenging because the cabbage can be large and unwieldy to hold.
For leafy greens, simply trim off the tips of the stems. (Do not cut the stem out and throw away. The stems are loaded with valuable minerals as they drew nutrients from the soil into the leaves.) Roll the leaves into cylinders and slice them crosswise into threads. If the stems are very thick, simply fold each leaf in half, exposing the stem. Slice the stem out of the green and cook separately. Continue with the method to shred the leaves after removing the stem.