you got two screws there. one is idle rpm the other is mixture. if its on the side of the slide thats closer to the airbox its a air screw on the engine side of the slide of the carb, fuel mixture screw.
turn it to around 2 turns out. 1 1/2 to 2 turns out, from fully screwed in. and dont turn it in hard. just find it closed then unscrew 1 1/2 to 2 turns. start your bike. it should run. if it hits but doesnt idle, then screw in the idle rpm screw some. more in means higher slide, means more air faster speed, more, faster rpms. if it bottoms out pretty quick as you screw it in maybe its turned up too high. you can look at the back of the carb maybe with a flashlight and look downit to see where the slide is when you turn in the idle rpm screw.
should just be sorta cracked. and when it starts, you up the idle to sort of a high idle rpm. like itd be high for you if yo8u set the idle at that.
then adjust the mixture screw for the highest rpms.
just sort of keep your idle rpm the same thou as you do it and lower the rpms if it gets up too high while your adjusting it. keep it about the same.
once its set. lower idle to normal idle.
if it goes all the way in, and is best there, then the jets too big or small or its clogged.
clean or up or down jet. if its a fuel screw itll be too rich. air screw, itll be too lean of a jet. or probbaly clogged, maybe.