On all hand planes, you control the depth of a cut by turning the adjustment knob. The knob usually moves the blade up or down. For the correct depth, you can start by adjusting the knob so that the cutting iron projects by about 0.5 mm. From there, you start planning as you re-adjust the depth to achieve a clean,slightly transparent shaving. I suggest that you test the amount on a scrap piece of wood before making a final pass on the actual piece.