In its simplest terms, to connect to the internet, you typically need an NBN connection, ISP router, and a connection between your device and the ISP router, be that via Ethernet cable or Wi-Fi connection. Ethernet cables are used for wired connections, requiring an Ethernet port on your device and a connection to the ISP router, while Wi-Fi allows for wireless connection. Certain devices within your house may benefit from a direct Ethernet connection, rather than relying on a WIFI connection which is more prone to interference.