You see the two, one on top is sticking out towards the edge. Do NOT turn this one.
You want to turn the one on the bottom. It should be recessed in further than the top one. You will need a 2.0mm hex head to turn it.
Here is how to turn:
--- Counter Clockwise (Left) for Earlier Gear Shift
--- Clockwise (Right) for Later Gear Shift
Make sure your engine is off b/f attempting to adjust the screw. You want to make adjustments in 90 degree increments. It doesn't take much to adjust the shift point. Simply give it a 90 degree turn & then drive it to see how you like it. Give it a couple of high speed runs to clear the carb out and let it get used to the shift point. If that is still too early, give it another 90 degree turn.
Just make sure you don't turn the top screw. That one actually should be thread locked from the manufacturer. If you turn it, you will break the lock seal & will need to put some more thread lock on it.
Later.....:mex: