In this picture you see the left foot accelerator with the guard in position in front of the original accelerator pedal.
To convert back to right foot accelerator, remove left one (quick release) and fold down the guard.
This is very user friendly system but takes some time to get used to.
If you drive for a long time with your right foot and must now convert to the left, it is sometimes better to change to hand controls.
A left foot accelerator with guard in place
Left foot accelerator guard removed in seconds