The goal in the first area is to get the beam through each of the nodes. In the second area the beam must be aimed at the panels and by using all four portals direct the beam to the receptacle.
Pick up the Cube and redirect the beam from the ceiling to the turrets in order to destroy them. Then aim the beam straight forward to the white panels.
6
Shoot your portals to the panels with the beam and the other portal on the wall nearest to the node.
Place your portals on the highest panels and then to the panels near the place where you picked up the Cube.
7
Go to the door and then proceed to the disassembly area.