1988 528E O2 indicator light won't turn off

I replaced my O2 sensor about 4 months ago with my Dad and the light has remained on I've tried to look online for some help and found it hard to find and the info I got was unclear. Does anyone know how to do this? Is there a reset button, if so where. I'm caretarded, so I need monkey proof instructions. I really don't want to take it in to turn off a light. Any help??

I have two BMWs and on the newer BMW the warning lights go off when the part is replaced. I have a 1988 528e as well and I noticed the lights do not always go off when a part is bad or replaced. My coolant light is always on but the temperature gauge says everything is okay, the coolant level is always good and I took the car to a BMW dealership and they could not figure out how to turn it off. I figure let the light remain on because when it comes to an oxygen sensor problem, you will know if you have a problem.

unhook your neg cable for 10 or 15 min. and then put it back on and see if it go's out as this resets your computer.