Try installing pulseaudio-utils and dbus-user-session inside container:
sudo apt install pulseaudio-utils dbus-user-session
As for the command:
bindis on the instance side, solistenis for the container side andconnectfor the host sidesecurity.uidandsecurity.gidis set to your user’s uid/gid on the hostuidandgidis set to your user’s uid/gid inside the container
If sound still doesn’t work, see Troubleshooting section, where you can find information about pulseaudio cookie and how to copy it to the container.