As mentioed in the intro, FPSF Pro relies on the base asset, however it's included in the Pro package so there's no need to pre install the base asset first. Other things like Mirror must be installed since the Multiplayer in FPSF Pro uses Mirror.
If Mirror doesn't get installed automatically make sure to install it.
Mirror Resources
You might want to take a look at Mirror's offical docs if you want to expand the networking even further.
