2003 Lexus ES300 How does

Holding the button is supposed to work. This from owner's manual: PRESETTING A STATION:

1. Tune in the desired station.
2. Push one of the station selector buttons (1-6) and hold it until a beep is heard. This sets the station to the button and the button number (1-6) appears on the display.

Each button can store one AM station and two FM stations. To change the preset station to a different one, follow the same procedure. The preset station memory is cancelled when the power source is interrupted by battery disconnection or a blown fuse.