Walkthrough (part 1):
-Take the redirection cube and reflect the laser towards the laser catcher in front of you. This opens the glass panels.
-Note: The area where you start will be called "Base A", the area on the other side of the panels, "Base B".
-Shoot a blue portal somewhere in base A and an orange one somewhere in base B (so that both are reachable)
-Now rotate the redirection cube 90 degrees clockwise, you should see another laser catcher. Activate it.
-Go through the portal.
-Walk over the active light bridge and receive the second redirection cube.
-Go back through the portal.

Walkthrough (part 2):
-Orientate the first redirection cube to activate the glass panels again.
-Shoot on two areas in base B, blue on the area marked with 1 light strip and orange on the area marked with 2 light strips.
-Go back to base A, orientate the first redirection cube to pass through the portal.
-Orientate the second redirection cube to reflect the laser coming from the portal onto the catcher that activates the glass panels.
-Go to base B.
-Through the open glass panels, shoot an orange portal on an area marked with 3 light strips (somewhere in base A).
-The door should open. If it doesn't, use the victory lift to return to base A and repeat this part of the walkthrough.