Add in a few cubes of wax.

For a mid size or larger warmer such as this one, use two cubes at a time, at the most. For a smaller size warmer, you only need one cube at a time. Adding more than the suggested cubes of wax to a warmer could lead to the wax not being melted all the way.

Turn the device on.

Make sure the device is powering on by observing the light indication.