Change WAN to LAN
You can configure the WAN port of the router so that it can be used as a LAN port. That's useful when you are using the router in repeater mode which the WAN port is not required. As a result, you can have one more LAN port.
Especially for GL-AR300M-Lite, it only has one Ethernet port which works as WAN by default. Therefore, you must connect to it via Wi-Fi. However, once you have connected to it, you can change its WAN port to LAN so that you can connect to it via an Ethernet cable.
Leave the WAN port of the router unconnected.
Connect your device to the router and access the web Admin Panel.
Go to Internet, click Use as LAN under the Cable section.
Click Yes to confirm.
You can simply revert the setting by repeating the above procedures. This time, it will show Use as WAN in step 3.