@Girlygirl this is what you need to do. It's two separate things. I normally don't even think about it because I turn down all volumes as well.
1) Set that "Do not disturb" option. It prevents any kind of notification from popping up on the screen.
2) there are multiple volume settings. I normally turn the main volume option all the way down. This prevents even email sounds from happening.
Yet there is just a phone volume setting. So pop up the volume settings by pressing either volume button on the right side of your phone...
You can turn all volumes down right there. Quick and easily.
Yet there's just a "call volume" as well, if you click on the circled levers button and turn it all the way down to off.
"Media volume" applies to all volumes. Which is the main volume selector. You can turn down more than just the call volume. Say the notification volume, while leaving the volume for everything up.
This will allow you to play videos, music and games normally. There is no specific volume lever for them. Just the "media volume" which is everything.
Doing both 1 and 2 you won't hear or see any phone calls.
Doing just one without two the phone call will still pop up a message. Also the call volume absolutely must be off. Not just turned down.
There is another options yet it's in the "See more"/"advanced" section of the second volume menu. There are tons of sound options including for vibration and separate apps. Far too much to go into on this.
