To load a Bostitch stapler, pull the top section of the stapler away from the bottom section, squeeze the latch and pull it towards you. For heavy-duty staplers, place the staples facing upwards. For desktop staplers, the staples should face downwards. Slide the latch back, and close the stapler.
To find out whether the staples have been properly loaded onto the stapler, place a piece of paper between the staplers and press the upper section of the stapler firmly against the stapler's base. The staple should sink into the piece of paper and fold the prongs firmly into the paper.