Open the parts bag and locate the black metal channels and screws.
Fit the black metal channels into the angled slots on the cutting board.
Assemble the black metal channels in the angled slots by screwing them in through the bottom of the cutting board.
Install the mat guide in the blank angled channels. It will slide back and forth in the channels.
Lift the guide rail and unscrew the slotted screws and metal tab from the wide routed slot in the cutting board.
Fit the squaring arm into the wide routed slot and align the slot in the squaring arm with the slot in the cutting board using the metal tab.
With the metal tab in place assemble the squaring arm using the slotted screws, and then remove the metal tab.
Loosen the knob on the bevel cutting side of the dual cutting head and slip in a blade. Then tighten the knob to hold it.
Lock down the blade holder on the straight cutting side of the dual cutting head and loosen the knob.
Slip a blade into the blade of the blade holder and tighten the black knob to hold it.
When both blades are installed, the dual cutting head is ready to cut either straight 90° (for sizing) or at a 45° bevel (for cutting a window).
Fit the squaring arm stop onto the end of the squaring arm.
Slide the squaring arm slot along the scale and lock it down at the size you want to reduce your matboard to.
Place a sheet of matboard in the mat cutter, under the guide and up against the squaring arm stop. You are ready to start cutting.