Megadrive 6 button mapping to Xbox Controller help

Hey, Been trying to map the buttons for a megadrive game (streets of rage 2 and 3) with my xbox controller through windows but i can’t get one button to work. When the games running i’ve gone into Controls, changed the device type to MD 6 button and have tried mapping the buttons. The problem is that i don’t know what maps to what. I also have two B buttons and no A listed, not sure why. Has anyone experienced this? and can anyone share a picture of their screen so i can see the mappings? Thanks