Thanks again arj0n for your reply - it's very much appreciated! Something's not working out for me here or I'm doing the wrong thing?
Hey Ciara.
Sorry, I left out a part because I thought you had figure that part out already. Maybe you overlooked something

I don't seem to be able to look at the drawing to see those columns?
The drawing is the key which is added to your inventory after using the notebook (found in the small bag) on Beth.
You should be able to look at this inventory item.
Where is the strange structure? - is there an area I've missed? I'm completely lost?
The strange structure is that strange machine, left of the screen in the room which entrance was blocked with laserbeams.
And no, you're not completely lost, just stuck, a little bit

So below is the part that probably contains something you might have missed.
This point starts when you arrive in Area 51.
WT Part 2:
Laserdoor:
Switch to Beth
Walk to the room with the crates
Tachy will follow
You'll end up at the double-door with an exit sign above it
Take the small bag
In the right-side corridor you'll see a toilet
Stand close and listen. Someone seems to be in need of toilet paper.
Follow your way through the coridor to the left
You end up at a laserbeam-protected door
Against the back wall you notice a desk and a computer.
The guard who usually sits there must be the person on the toilet in need of toilet paper
Look at the monitor
Beth notice a password is required
Use the keyboard below the monitor
A pop-up screen is shown asking for a password which you don't have
Click exit to leave the password screen
Walk back to the toilet
Walk back and forth in front of the toilet and listen to the person sitting on the toilet
After a little while the person thinks you're his colleague
Now he reveals the password
Walk back to the computer
use the keyboard again
Enter password: Roswell47
Click the Confirm button
The laserbeams are now disabled
Walk to the left
You're now entering the room with the alien machine... (
walkthrough continues here)