Your wi-fi connection is managed through the Fitbit app on your mobile device.
From the ‘Today’ tab in the Fitbit app, tap your profile picture in the top left corner > Sense tile.
Tap Wi-Fi Settings > Next
Tap Add Network and follow the on-screen instructions to connect the Wi-Fi network.
You may need to restart the Fitbit watch to sync the Wi-Fi connection by pressing and holding the haptic button on the left of the watch for 10 seconds until you see the Fitbit logo appear on the display.