How to fix 2004 Ford Taurus sel airbag light?

I have a 2004 ford taurus sel that I got from a lady who got it from a guy that bought it from the auction. So the car has some minor wear and tear but it does drive. It does have a 44 on the battery, so i don't know if thats the problem like if its weak because it dies after charging it. But what I also need to know is how to get rid of the solid yellow (non blinking) airbag light.

Probably a bad sensor, YouTube can tell you how to diagnose and fix