The update isn’t pushing out over-the-air, so you can’t update from just your phone alone. Instead, you’ll need to update the T-Mobile LG G3 via LG’s Mobile Support Tool (download it here). This means you’ll have to download LG’s updating software to your desktop computer and like an animal, connect your device via USB in order to apply the update.
We’re not sure how long the update will only be available in this way, but it’s kinda neat that a manufacturer is giving users the option to update early with this method rather than waiting around for a carrier to push out new software to their device. Again, it’s entirely possible the update — which at the time of writing, still hasn’t been green lit by T-Mobile — will be rolling out to G3s in the coming hours/days/weeks. So, if this process is too much for you, just sit tight. Lollipop will be here soon enough.