This TV has the active 3D transmitter built in to it in some regions. It is included for the model sold in the U.K.
You need to register the Active 3D glasses before they will work with the TV. To register the glasses, turn on the TV and bring the glasses within .5m of the TV. Then press and hold the power button on the glasses for 2+ seconds (until the power button blinks alternating green and yellow). When the registration is successful, a message will show on the bottom of the TV and the green light will stay on for 3 seconds. This will need to be repeated if you use the Active 3D glasses with another TV and then use them again with this TV.
Now you need to activate the 3D feature on the TV. Press the 3D button on the remote or press the control bar on the Touchpad remote and slide the touch pad to the 3D icon and select it. Then choose your 3D option. You may also need to adjust the 3D display settings from the Home button. Press Home and select Settings. Then choose Display and then 3D.
The manual for the KDL-55W829B is available here: http://www.sony.co.uk/support/en/product/KDL-55W829B
. The Help Guide, http://download.sony-europe.com/pub/manuals/tvhc/14HE468112-EN-Print.pdf
, has the information on using the 3D feature starting on page 56.
I hope this helps.