reseting of the air bag

You need a high-level scanner to get near the airbags. No, it isn't cheap; you'll pay just about $400 to have the option like the 2nd scanner I use as it's only available in all system scanners.

Why do you need to scan the airbag system? If you get in a wreck that blows the airbags, you usually need to replace both the airbags and the black box(es) used by the SRS/Airbag system unless you can find a way to reset them at home or send them off to be reset. In order to better help you and see what you need to do to reset it, we need more details, such as whether you got into an accident.

In addition to the actual airbags, the black box that trips the light if it blows is a one-time part that you get reset by a specialist or replaced. It's not something you can readily reset. You need to have a specialist reset, or you will have to replace it if it can’t be readily reset. The components you replace by default with an airbag event also include the seatbelts since the tensioner will not reset after an accident as it's a one-time use part that gets replaced in the accident repairs.

If you fully intend to try and fix an airbag issue, you have to make sure that the main 12V battery is disconnected and make sure you know how to work with it safely as even one mistake like plugging a new/used airbag into the car without making sure the main 12V battery is disconnected WILL blow up an airbag in your face. To be quite frank about the best way to do it safely for a beginner, it should sit for ~30 minutes-1 hour to make sure you can safely work on the airbags.

Just to be clear: If you drain the 12V system by leaving the battery disconnected for a little while the airbags pose little to no danger, but precautions aren't a suggestion when you're messing with the airbags.