Thermador cooktops typically do not have a separate "On" switch like a traditional appliance. Instead, they often have individual burner controls that allow you to turn on and off each burner independently. The specific design and layout of the controls may vary depending on the model and type of cooktop. Here's how you can use the burners on a typical Thermador cooktop: 1. Gas Cooktops: For gas cooktops, each burner usually has a dedicated control knob. To turn on a burner, simply turn the corresponding knob counterclockwise to the desired heat level. Some models may have electronic ignition, so you might hear a clicking sound as you turn the knob, indicating that the burner is lighting. Once the burner is on, you can adjust the flame height by turning the knob. 2. Induction Cooktops: Induction cooktops use electromagnetic technology to heat the cookware directly. To turn on an induction burner, place an induction-compatible pot or pan on the cooking zone and adjust the power level using the touch controls. The burner will activate once the cookware is detected, and you can adjust the heat output as needed. 3. Electric Cooktops: Electric cooktops typically have control knobs for each burner, similar to gas cooktops. Turning the knob counterclockwise will activate the burner, and you can adjust the heat level accordingly. Remember to follow the safety instructions in your cooktop's user manual, such as ensuring proper ventilation and using appropriate cookware. If you're unsure about operating your specific Thermador cooktop model, it's best to refer to the user manual or contact Thermador's customer support for guidance.