Sit on the vehicle like you would for normal operation. Make sure the transmission is in neutral, the parking brake is set, and the fuel valve is on.
Place the engine stop switch in the "On" position. This switch is red and can be found on the left hand grip next to the lights and choke switch.
Turn the main key switch on. The key hole can be found in the middle of the handle bars right above the gas tank. Turn the key all the way to the right until it stops.
Squeeze the left brake lever and press the start button at the same time. The starter will not engage unless the left brake is applied. If the starter engages but the engine does not start, set the choke switch -- located under the red engine stop switch -- to the full position and try again. Once the engine starts, release the start button and let the engine idle on its own.
Let the engine warm up for at least five minutes before operating it. If you used the choke when starting, be sure to return that lever all the way to the right to turn it off.