Using your Ethernet cable, connect one end to the first port on the back of your modem. Connect the other end to your extender's port with the globe icon, or to either port if no globe icon is present.

If you received the optional network switch to connect more devices directly to Ethernet, connect it to the second Ethernet port on the extender connected to the modem or either port of any additional extenders.
Note: It’s possible your extender will need to update before it connects. (This can take up to 10 minutes.)