Connecting to the internet with the Ethernet provides a more stable connection and avoids potential video buffering. You can locate your router closer to the VBox and TV or use a longer cable to connect the router to your VBox. Plug the Ethernet cable into the LAN port of your modem/router and into the VBox. See more details in Ethernet Settings.
If you have a wireless router at home, you can connect your VBox wirelessly. See more details in WiFi Settings.