- Next to the chamber number.
- Above the orange portal.
- On the right wall just before the chamberlock.
This chamber contains no doors, buttons or cubes, but is simply to test that you grasp the basics of how to use portals. The orange end of a portal is permanently in place on the middle pier of three; you're on the first, and the chamberlock is on the third.
To get to the middle pier, create a portal in a wall next to you, and walk through it; it will take you straight to the middle pier.
To get to the third pier, fire the portal gun at a wall on the third pier, and walk back through the permanent orange end of the portal. Although you just came through this portal from the first pier, since you've changed the location of the blue end of the portal, you now arrive on the third pier, and can exit the level. An important fact to remember is that when you fire the portal gun to create a portal end of a specific colour, the previously-existing portal end of that colour will disappear; you can only have one blue and one orange portal end at a time.
Well done. Remember the Aperture Science "bring your daughter to work" day is the perfect time to have her tested.