What are the torque clutch settings and what are they used for?

The drill has 24 torque indicator settings on the front of the tool. Settings 1–4 are for driving small screws, 5–8 for soft materials, 9–12 for soft and hard materials, 13–16 for hard wood, 17–20 for large screws, and 21 and above for heavy drilling. Rotate the adjusting ring to the desired setting. (Page 12)