I am building a MCP using Arduino Mega, but have difficulty with the momentary button switches, don't know what pin to solder to life or ground the same with the legs of the build in LED. The button switches I use have has a LED built in (see attached pictures). There is a lot of switches and I think I can ground them all in series. No sure if this the right technical word.
I know that the LED long leg is positive and the sorter one in the negative. I further think, not sure, that the LED has nothing to do with button action as you program it in MobiFlight.