Canon SPEEDLITE EL-1 Advanced User's Manual page 186

6.
Set the A:B flash ratio.
Push the joystick vertically to select an item in the figure.
Push the joystick to the left or right or turn <
compensation, and push the joystick vertically.
7.
Setting the exposure compensation amount for firing group C.
Push the joystick vertically to select an item in the figure.
Push the joystick to the left or right or turn <
compensation, and push the joystick vertically.
8.
Check that the flash is ready.
Check that the sender unit's flash-ready lamp is lit.
Check that the receiver unit is fully charged.
186
> to set the amount of
> to set the amount of