Plug in your soldering iron and let it become heated. Most soldering irons should reach temperatures high enough to melt solder in 10 minutes.
Apply the tip of the soldering gun to the contact on the circuit board, or other electronic device, from which you desire to remove solder. Apply only enough heat from the tip of the gun so that the solder melts, and the circuit board does not come into contact with prolonged heat.
Squeeze the center of the solder sucker pump with your thumb and middle finger. Then position it directly above the melted solder. Release your fingers to create the vacuum effect that causes the melted solder to be drawn up into the pump.