Prusa Research MMU3 Manual Del Usuario página 148

PASO 6 Pro tip: Loading using the buttons.
You can also load a filament into the MMU using the buttons on the unit. Next time
you load a filament, use the method you prefer. Either from the LCD menu, or using
the physical buttons.
While the MMU is idle; (indicated by ALL LED lights OFF)
The middle button starts or aborts the filament loading to MMU.
The side buttons move the selector left and right to switch filament positions.
Use the side buttons to move the selector onto the desired filament position
indicated by the selector being aligned with one of the lines on the label-plate.
The ongoing loading process is indicated by a blinking green LED light for the
respective filament position.
Stable green LED light means the given filament is loaded to extruder.
Note, after you issue a command to the MMU unit, wait and let it finish the
operation. Don't rush. Don't play around with the printer in the meanwhile. Let it
finish first if the MMU unit does something (homing, loading, unloading).
148
11. Primer comienzo
Ensamblaje Original Prusa MMU3