CAME BY-3500T Manuel D'installation page 28

Position the gearmotor above the mounting plate. Caution! The electrical cables must pass under the gearmotor box.
Lift the gearmotor 5 to 10 mm up from the plate, using the threaded steel feet for any subsequent adjustments between the pinion and the rack.
Unlock the gearmotor. Rest the rack on top of the gearmotor pinion.
Weld or secure the rack to the gate along its entire length.
Assemble the rack modules by using a piece of scrap placed under the join point, securing it using two terminals.
N.B. if the rack is already present, proceed directly with adjusting the pinion/rack coupling distance.