You match your dial on the autopilot to the compass on the boat and then turn on the unit, matching the two headings, after that, the autopilot keeps you on your compass heading. To adjust your heading after the unit is on, you just turn the big dial on the autopilot. There is a knob that you turn to adjust the frequency of the autopilot adjustment to the steering, from slow (more frequent adjustments), to fast (less frequent adjustments. I have been very pleased with this unit, even thought it is older, and does not have all the fancy extras like the new ones, it certainly is an extra set of hands on the boat. I went out by myself quite a few times last summer, and on a 28' boat an autopilot is the only way you could accomplish that.