For legacy network-connected Tablo models, the blue reset button is on the back right of the device. Use this article for links on how to access Wi-Fi settings on other legacy Tablo devices.
If you want to switch from Ethernet to Wi-Fi, first remove the Ethernet cable from the 4th Generation Tablo and then reboot it by quickly tapping the reset button on the bottom.
The Tablo will then boot into Wi-Fi setup mode. Complete the Wi-Fi setup process on your iOS or Android tablet or phone.
If you want to switch from Wi-Fi to Ethernet, attach one end of the Ethernet cable to your home's Wi-Fi router and the other to your 4th Generation Tablo. Next, quickly tap the reset button on the bottom of the Tablo. Wait for the blue LED to stop flashing. Once the blue LED is solid, your Tablo is now online and using the Ethernet connection.