Which options you use and how many entries you have in the Input Mapper Blueprint depends on how you want the keyboard to act with the control.

For a simple toggle control such as V for Wipers where you press the 'V' key once to turn the wipers on and press the ‘V’ key once again to turn them off, you would

need one entry in the Blueprint:

For a control such as X for Sanders where you set the control anywhere between on and off with one keystroke, you need two entries in the Blueprint:

For a control such as H for Headlights where you use the 'H' key to increase the control and 'Shift-H' to decrease it, you need four entries in the Blueprint: