Condition your mold using a small amount of soybean or vegetable oil. Thread one end of your wick through the hole in the mold and secure it with some putty, be sure to seal the hole around the wick. If using a tabbed wick trim the tab off the other end and pass the wick through a wick holder. Secure the wick tightly using a clip or a peg, check that the wick is running up the centre of the mold. Follow the instructions for the wax you are using and proceed to fill the mold.
Suggested wick sizes are a recommended starting point only and your own testing is always required to determine the best wick for your candle recipe.