Hi
OK, assuming the NAS default ip address is 192.168.1.226, on the workstation using the NeworkManager applet create a profile called say NAS_1 and in the ipv4 section set the drop down to manual and enter the same subnet ip address eg, 192.168.1.10/255.255.255.0 and hit save, turn off the DNS and routes buttons.

Plug in the cable to the ethernet ports, open your browser and put in the ip address and port if necessary, eg http://192.168.1.226:8080.