The airbag light is notifying you that one or more of the sensors within your airbag system is faulty or malfunctioning. Depending on the system that's installed in your car you should have front and rear impact sensors. These sensors send a specified voltage back to the SRS control module. You will need a diagnostic scan tool to identify which part or parts of the system are malfunctioning. Upon identification of these parts you can order them from the Hyundai dealer. They should also be able to help you with the specific location of each sensor. Replacement of the old sensors are fairly easy, typically a one wire connection along with a left hand threaded bolt. Locating the sensor and gaining access to it are typically the most challenging parts of the job. The sensor is usually buried under a bumper cover or in some other hidden and protected area.
I hope this info helps,