Remove door panel. The panel is held in place with two screws. One on the center of the door panel and the second by the door handle. Once the two screws are removed you can pull out the door panel. Make sure to disconnect all the wires before you pull the panel out.
Remove old window switch from the driver's door panel. To remove the window switch you will need to use a flat screwdriver to release the switch from the housing. There are no screws for the window switch.
Now you should be able to remove the window switch from the door panel.
Install new window switch. Press it in place until it all the tabs lock in. Make sure to reconnect the electrical connector. Reinstall the door panel in reverse order. Make sure to slide it at the channel near the glass.
Next, install the door panel.
If you need further information on how to replace Hyundai window switch take a look at the shop manual.