Canon SPEEDLITE EL-1 Advanced User's Manual page 147

4.
Set each firing group.
Set the flash mode of each firing group by operating the sender unit.
Push the joystick vertically.
Push the joystick up / down / left / right or turn <
group, then push the joystick vertically.
Setting the flash mode
Push the joystick up / down / left / right or turn <
mode from < > < > <
147
> to select a firing
> to select the flash
>.