If you're having problems starting it when cold and you don't know much about engines...then be sure you are setting the choke when it's cold. That's the knob sticking out of the left side of the carbs...pull it out before trying to start. You could also try turning the fuel valve to the "prime" position for a minute before starting, if the float bowls aren't full, then you're spending time cranking the engine just to fill them before there is enough fuel to start the engine.
...and as stated above, give the engine some time to warm up before reving too much. You need to get the oil circulating and allow the engine parts to come up to operating temperature. Cold engine parts are loose fitting, they are all designed to be run while warm.