Push down the control knob of one of the two burners, hold it down, and turn it clockwise to the high position (big flame symbol).
While keeping the control knob pressed down, push the small red Piezo ignitor button, located directly next to the control knob. You will hear a loud click. Do not release the control knob yet.
Keep the control knob pressed down for 5 more seconds in order to deactivate the thermoelectric safety device. Check that the burner is lit by looking into the front opening of your Otto Grill, keeping a minimum distance of 12 inches / 30 cm. If ignition was successful, a light blue aura will appear under the lit burner.
If you do not see an aura or feel heat building up, press the red Piezo igniter one or more times.
Check again for a blue aura and heat. If successful, you can release the control knob.
In this short video (German only), Otto shows you how to ignite his grill.