For the Google Project Tango, how can I make a door prefab able to be entered through when I walk through it using the Augmented reality app?

I would tap the screen to spawn a door and I want to walk until I touch the door, and when I do, I would switch to a different scene with an alternate environment. I want to know how to actually switch the scene upon touching the door, and what procedures are needed to fully complete this process. Thanks in advance!