You didn't mention which lenses you use, so bergat is correct about setting the aperture on the lens, if you use XF lenses. For XC lenses (no aperture ring), you set the aperture with the front command dial, so to set an XC lens to auto, turn the command dial beyond the smallest aperture, and you will see the readout change color and display your wide-open aperture value. Your readout will also then display "A" in the lower left of your information display. Voila! Automatic Mode.