Using the Hella horn kit is straightforward. First, find a suitable location to install the bracket that comes with the kit. You can use the included mounting hardware to secure it firmly in place. Next, connect the wiring harness to the horns and then to your vehicle's electrical system. Make sure all connections are tight to avoid any electrical issues. When it comes to using the horns, just press your vehicle's horn button as you normally would. As for maintenance, it's a good idea to check the connections regularly to ensure they remain tight. You can also clean the horns occasionally with a soft, dry cloth to keep them looking good. Keep in mind that this kit is not suitable for the WRX GT model, so double - check your vehicle's model before installation. Also, make sure you follow all local laws and regulations regarding horn usage.