Prusa Research MMU3 Manual Del Usuario página 125

PASO 3 Attaching the MMU unit (part 2)
Make sure the unit is in the middle of the frame. Once we engage the clamps, it
won't move left and right as easily anymore.
Press the back part of the MMU3 unit downwards slightly, until the clamps lock to
the frame.
Check that both bottom clamps on the unit are fully engaged.
If you need to remove the unit from the frame, simply lift the back part up to
disengage the clamps.
PASO 4 Guiding the MMU cable
Now, we will guide the cables from the MMU unit into the printer.
Make sure the printer is turned OFF and unplugged from the wall outlet. Do not
ever connect or disconnect the MMU unit while the printer is ON.
Guide the cable bundle from the MMU unit into the box. The cable should be
placed just next to the printer's frame.
You can fix the cable to the MMU3 holder using a zip-tie in marked location. Make
sure it points to the side - not down. Otherwise, it might interfere with the extruder
cable while printing.
Guide the cable into the open part of the electronics box.
10B. Configuración y Calibración MK3S+
Ensamblaje Original Prusa MMU3 125