Here's how to conserve the battery life of your Nokia Lumia 820:
- From the Start screen, swipe to the left.
- Scroll down to and tap Settings.
- Tap WiFi.
- Tap the WiFi networking switch to enable it. The handset will automatically search for available networks.
- Tap the required wireless network.
- Enter the wireless password, then tap done.
- A connection to the wireless network has been made.
That's it - connecting to the wireless network is done.