Mac Mini private network

I am trying to set up a very simple network using a Netgear 5 port Gigabit switch, a Mac Mini, a Seagate Central 4Tb NAS and an Apple TV to serve movies to my Samsung TV.

I followed a guide on WikiHow, connected up all the devices, set the IP of the Mac manually and assumed that would be that.

I am far from expert in this area so as I cannot see anything under "shared" in finder I am now at a loss as to what to try. Is there something I need to do to tell the Mac what is there? I tried "connect to server" but none appear to be there.

The 3 lights on the switch corresponding to the ports connected are green and flash occasionally so they appear to be connected. I do not have an internet router where the devices will be deployed hence the wired solution with switch.