On the bottom of the carb, infront of the float bowl is a brass screw, this is your pilot mixture. Screw in is to lean the mixture, screw out to richen.
The method I would use is as follows, screw all the way in until lightly seated being sure to count the amount of turns it takes. As a base line guide, screw back out to 2 1/2 and see where you are at that. You may already be there, we don’t know.
Alternatively you could turn in 1/8 turn at a time. Remember to clean your spark plug after each adjustment so you get an accurate plug reading.