The first thing you'll find on this page is the slider to control the system master volume and adjust all sounds. Under 'Other sound options,' click the App volume and device preferences option. To access and customize app volume and device preferences, do the following: (This experience replaces the Volume Mixer, which is still available in the April 2018 Update.) The new Sound settings also include a number of advanced options to control volume and input and output devices. How to manage advanced Windows sound options using Settings You'll notice that the 'Volume Mixer' is still accessible, but it'll eventually go away as these settings can now be found in 'App volume and device preferences' page.
