1) Go into your G-mail and select the Gear icon in the top right.
2) Click "See all settings"
3) Stay in the "General" tab and scroll down until you see "Desktop notifications".
4) Change to prefered setting.
1) Go into your G-mail and select the Gear icon in the top right.
2) Click "See all settings"
3) Click the "Chat and Meet" tab at the top.
4) Click the "Manage Chat Settings" button.
5) Toggle the "Allow chat notifications" option.
There are additional options in this menu or other types of chat notifications and the ability to set DND hours