Using your Hella horn kit is easy. First, make sure your car is turned off. Then, locate the appropriate place to install the horns using the provided bracket and mounting hardware. Connect the wiring harness to the horns and the car's electrical system following the included instructions. Once installed, turn on your car and test the horns. Note that this kit doesn't fit the WRX GT model. For maintenance, keep the horns clean from dirt and debris. Periodically check the wiring connections to ensure they're secure. If you notice any issues with the sound or functionality, consult a professional mechanic.