The small orange button is designed so that you can hold the throttle on a little when starting. Place your hand over the dead mans lever on the top, pull the throttle in and hold it with your forefinger, push the small button in with your thumb and hold it in while letting the throttle off. You should find, if you look at the top of the carb while doing it, that the throttle comes of rest, and then is held on ,just a bit, by the button. If you "blip" the throttle, the button should "ping" out to it's original position.
Other than that, the starting procedure will be the same for any other small two stroke.
Do the above.
set switch to start.
prime the bulb a couple of times.
Turn choke on.
pull rope untill the engine coughs.
Turn off choke.
pull engine over again and it should go.
Don't keep pulling the engine over on choke after it's coughed for the first time or you will flood it.
Let me know how you get on, and if you need any more help, sing out.