how to reset the battery not charging light?

Hello,

The low battery charging light goes away with the correct out put of the alternator to the battery. You do not have to reset that light.
That light being on could mean the issue still exists.
First test the alternator output to the battery. You can do this by connecting a voltmeter to the battery. The voltage out put should be 13.6 to 15.2 volts.

Here is a helpful video:

https://youtu.be/Z-p4dMJUpUw

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Please note that many times due to bad wiring the alternator might not charge the battery properly. So it is important to check the wiring as well.

Please let me know of any questions.
Thank you.