Place the short leg of the Allen wrench into one of the screws on the back of the chair. Note that some holes may also be part of the armrests, holding both back and armrest together. Some screws may also be on the bottom of the chair.
Turn the Allen wrench clockwise several times until you feel the screw loosen up significantly.
Remove the screw by twisting it with your hand clockwise until completely removed.
Repeat the above steps for each screw attached to the chair.
Lift the chair back out of its base.