3 pos switch help

[Charlie6017]

Can someone post the proper way to mix the 3 pos switch for the flight modes in mission planner? Even the 2 position gear switch would be fine. I had downloaded someones hex file or eepe file with the 6 pos switch and that was working fine but then i dont know what happened and now its not working for me. I just need to have a basic understanding of what goes into mixing these channels. I dont understand the source field...Full Half etc. I put ch5 tofull and set the switch to gear and have the the receiver from ch5 into ch5 on the apm but cant get any switch to work. So if someone can lead to me the basic 2 pos or 3 pos mix that would be great. Thanks