Help Select silent through file manager

[Android Question]

Hey guys,
I'm using a galaxy s7 edge but I still get sound notifications when my phone is set to vibrate. I went to the Gmail settings page, clicked on my account, clicked on the inbox sound and vibrate. However, when I click the notification sound tab (to set it to silent) theres no option, all that pops up is a file manager screen where I can set sounds from the device or SD card, no way to select silent.
Thanks for your time,
Matt

 

[Dannydet]

The play store has some 3rd party apps for separate volumes that should help