Keyboard- Azerty to Qwerty migration issue

Hi.

Have an issue with a qwerty keyboard. I used to have a french azerty keyboard out of which I migrated to my brand new macbook air in an english environment.

First of, keyboard values are not working properly as even though i switch language input source, several input buttons are not reflecting their values properly.

Second, in order to solve another issue -keyboard backlight- I was told to act on the F5 and F6 buttons. Didn't work out either.

Please help me out.

Thanks.