Each device connects directly to the switch.
The 360 comes with a 20' Ethernet cable so you need two more to connect to the switch.
There are several lengths available with the 20' version being AS EC 20E.
The displays have an Ethernet port on the back for the connection.
Humminbird Helix 12 SI, 1198c SI, 1198c SI, ONIX 10 SI NT, 360, RC-1