For example, when mapping the aileron axis, you can select one axis or you can select two different ones. Looks like all the commands are like that. Why is that?
I believe the first column is for default mappings and the second one (right column) is for your modified mapping.
Does the modified override the default or do they work at the same time?
The modified mapping will be in a different configuration of your peripheral , look at he top, where the name of the peripherals is located, it will ask you to give it a name,add some number or ltr. at the end.
One is an axis mapping (analog)
The other 2 are for digital mappings (button press)