Turn off sound notification for GMAIL on applemac

I have just purchased a new mac air.

i use gmail , and it is annoyingly pinging me with every email !

The sound notification > via settings> notifications> mail- does not have a sounds button i can turn off ( unlike the other apps)

I have gone into gmail and turned off notifications- and this has made no difference.

Can anyone assist ? before i throw the laptop out of the **** window !!!!!!!!!

many thanks all