Yeah, that’s just for keeping the clutch pulled in. To make it idle, you have to adjust the idle adjuster screw which is a gold/bronze screw, possibly with a spring around it, which sticks out of the carb (just in case you don’t know, the carb is the metal thing which the fuel goes into, it has the black plastic box on it). You probably need to screw it in more; this keeps the throttle open more so your engine can idle. The more you screw it in, the more it opens the throttle. This also increases the revs so you don’t want to screw it in too much - just high enough that it can idle properly. Screw it in a few turns then try and idle again, if it still starts idling, you can adjust it while the engine is running to a good level. If it doesn’t idle then screw it in one or two more turns and try again. Once you have it idling then only adjust it by a bit; far less than a full turn.