the cleaner wax removes contamination, swirls etc, but contains abbrasive materials to do so. It is good to wash and dry, the use a cleaner wax if it's been a while and the surface isn't smooth. Using a clay bar before thand can help as well. Then use the cleaner wax, then if you want a polish or glaze then the actual wax.

Using a cleaner wax too often can do damage to the paint. For great instructions either search through the appearance forum or see the RX guide at http://www.meguiars.com/CarRx.cfm