Step on through, open the door and you’ll find yourself inside a tall enclosed room. You need a portal on the white wall on the ground floor and the next one needs to be on the wall up and to the left (look for the metal walkway above).
Once you’re on the metal walkway, position yourself so you’re overlooking the floor below and you should notice two patches of usable areas. Place a portal on each and then drop down into the one below you, as you ascend through the second portal, turn to your left and you should notice the light wall on the upper central part of the room.
Quickly place your entrance portal here, so as you descend through the portal below, you’ll be catapulted over to the walkway, walk through the door/fore field and head on through the door to the next part.
MISSABLE ACHIEVEMENT/TROPHY ALERT!
If you go to the top floor initially and go inside the office space, look for the hidden door in the left corner of the room. Open it up, then hit the remaining three door buttons to trigger the 'Door Prize' Achievement Trophy. Also, if you walk outside into the shipyard, you’ll also be awarded with the 'Ship Overboard' Achievement/Trophy! Bonus!