You're going to melt the solder joint through the wick, allowing the wick to draw the molten solder into itself.

Apply a bead of flux to the solder joint.

Place a clean portion of the solder wick on top of the solder joint.

Press the soldering iron tip firmly against the wick for 2-3 seconds. You're trying to heat the wick hot enough so that it melts the solder underneath it.

If you heat the circuit board continuously for more than 10 seconds, the excessive heat may damage the solder pad.

If the wick doesn't draw solder, you may need to increase the temperature. The wick may also be oxidized due to age—apply more flux or try a newer roll of wick.

As the solder saturates the wick, slide the wick so that a new portion touches the joint. You'll know it's saturated when the wick's color changes from copper to silver.

Once most of the solder has soaked into the wick, lift the wick and tip away together from the joint.