Stihl MS 230 Chainsaw Carburetor Adjustment: H, LA & T Screws - Air-Fuel Mixture & Spark Plug

Hello. I would like to properly adjust the carburetor on my stihl MS 230 chainsaw. I have 3 screws: H, LA, and one unmarked (probably a T). How to adjust the carburetor so as not to seize the saw? The saw is after replacing the spark plug, rings, sealants and diaphragms in the carburetor. Now the saw runs very nice. It spins elegantly up and down smoothly. But what worries me is that the wrong adjustment of the air-fuel mixture can lead to seizing, and then the saw goes to the trash, because it will not be profitable to repair it. I will add that after a dozen or so minutes of work, I unscrewed the spark plug and checked its condition. It was black but not that much. I know the color of the candle should be like the color of coffee with milk .

I don't want to take it to the service center anymore, because after 1 I don't have much time after 2 I put quite a lot of money into this chainsaw after 3 there is one service in my city, sometimes I pass by this service, I even happened to go inside and honestly ... I'd rather do it myself... There are brains on this site who recently graduated from school (of course the easiest one) and probably learn on someone else's equipment. Of course, you'll think that I know better than the people on the site. Unfortunately, that's not the case... There are simply inexperienced people out there and I'm afraid to entrust them with my equipment that I had to pay for . I've seen these pictures before. They don't tell me anything. How am I supposed to unscrew the screw H by one turn since there is a plastic limiter and it is impossible to unscrew it by one turn. When I turn this screw H, I do not feel any changes in the engine's operation.