Open the door, turn right, open the door facing you and move forward.
Wait for the moving panel to extend. Place a portal in the test chamber and the other near you, then pass through it.
Look up and fire the same portal as previous through the grating, then go through the other portal.
Place the first portal, through the other grating, on the upper floor, then pass through the other portal.
Place the second portal, through the two grating, at the bottom. Grab the Weighted Storage Cube and go through the portal.
Shoot the first portal above the right ledge, and put the cube on this last.
Put the portals on the two markers. After passing through the portal many times, shoot the right portal -the one on the ceiling- on the extended panel.
With the momentum you gained, you should land behind the Turrets. Knock out these then go a the end of the room.
Place the first portal on the floor and the other on the wall, on the turrets' lasers level.
Just after going through the portal, fire the same portal as the previous on the wall behind the turrets.
Pass through the portail again, knock out the turrets and stand on the button.
Place the first portal on the ceiling, then go through the other next to you.
Along the corridor then shoot the same portal as the previous through the grating, on the ground level.
Come back, push the Switch and pass through the portal under the vertical door.
Take the cube, go through the portal and put it on the button.
Go on the supplementary ledge, then look up. Place a portal in front of the exit door and the other on the bottom's floor.
Jump through the portal and proceed to the Chamberlock.