Unscrew the three screws on the back of the plug. They should be loose enough to allow a wire to be inserted into the contact points without the screw falling out completely.
Strip 2 inches of plastic sheath from the wire. There should be three smaller wires within the sheath. Strip a half-inch of sheath from each of the smaller wires. Twist the exposed copper section of each of the three wires into a tight bunch.
Insert the wires into the corresponding contact points. The colors of your wire may vary depending on whether you are using standard flex or building wire. Insert the active wire (brown or red) into the contact point marked "A". Hold the wire in place and tighten the screw to secure the wire. Don't screw the screw in too tight or else you may tear the copper wire. Repeat the process for the neutral wire (Blue or black color) and the earth wire (green and yellow color), securing them to the "N" and "E" contact points respectively.
Unscrew one screw from the main cable holder and remove the screw completely. Most plugs use a small plastic "gate" secured by screws to hold the cable in place. "Swing" the gate open and place the wire in the holder. Close the gate again and secure the screw back into place. Make sure the wire is held in place around the outer sheath.