$ sudo apt-get update
$ sudo apt-get install pulseaudio-module-raop 

pulseaudio-module-raop is installed in your system.

Make ensure the pulseaudio-module-raop package were installed using the commands given below,

$ sudo dpkg-query -l | grep pulseaudio-module-raop *

You will get with pulseaudio-module-raop package name, version, architecture and description in a table

pulseaudio-module-raop package basic information: