The video by our French friend is pretty good. There is only one needle valve, the main mixture screw on the side of the carb. It’s going to be quite sensitive. Start with very little opening, and go roughly one clock position at a time (1/12th of a turn) when adjusting. The other adjustment is the idle stop. It’s located on the front of the carb, not far from the exhaust stack. Judging from the video, note the successful idle stop
setting Is an opening that only spans half of the carb inlet.
Beyond that, insure the engine is getting strong fuel supply, with no air in the fuel line, and make tiny adjustments. You’ll get it.