Does the car adjust its idle speed (carburetor car) and use mixed gas at the same time? How to adjust it?

After the hot car starts, loosen the mixing ratio screw for three and a half turns, then adjust the throttle screw to the lowest idle speed, then adjust the mixing ratio screw to the fastest speed position, then adjust the throttle screw to the lowest speed, and then adjust the mixing ratio screw to the highest speed, and so on for several times! Non-professionals generally do not adjust the mixing ratio screw, but only adjust the valve screw.