Steam: Fix notifications not working/showing | In-game & Desktop

Watch the video:

0:00 - Explanation
0:20 - Missing notifications
0:29 - Do not disturb mode
1:02 - Settings
1:19 - Fix missing notifications in-game

This simple fix should work for all operating systems, not just Windows. There are simple things that you might have missed, and this video should get you going in the right direction really quickly.