The ethernet switch needs a feed from a RJ45 jack used for ethernet. I have 2 of these switches connected to my Netgear Orbi router to feed additional ethernet devices. My Orbi router is fed by a Spectrum cable modem router via an ethernet cable and the Orbi router is broadcasting 2.4 GHz, 5 GHz and 10/100 RJ45 Ethernet jacks.
Hope this helps.