PulseAudio is a network-capable sound server program. A sound server is a background process accepting sound input from one or more sources (processes, capture devices, etc.), that is able to mix and redirect those sources to one or more sinks (sound cards, remote network PulseAudio servers, or other processes).
To install PulseAudio on Debian Linux first update package repository:
sudo apt update
Next install PulseAudio:
sudo apt install pulseaudio
Now reboot your computer.
Using PulseAudio Volume Control Graphical Utility:
PulseAudio has a graphical frontend PulseAudio Volume Control, which you can use to easily configure PulseAudio sounds graphically.
It is not installed by default. Run the following command to install PulseAudio Volume Control:
sudo apt install pavucontrol
Also to change sound volume by hotkeys you need amixer utility install it by command:
apt-get install alsa-utils