To add to Chaya's excellent advice, most general purpose scan tools cannot reset an airbag light; it usually requires a dealer tool to access the airbag system. So even after you fix the problem you will most likely have to find someone with the proper tool to turn the light off.
If you do find someone with the proper tool, they will be able to scan the airbag system and tell you why the light is on in the first place; that will tell you what needs to be repaired. It could be as simple as a broken wire on the seatbelt or as dangerous as a defective airbag; no way to tell at this point with the information you have.