I built this today at work. It's my new desk. It actually took me a bit of time, because I'm not really accustomed to reading figures & having 8 different sizes of nails & screws.
The keyboard drawer, plus the two side drawers all had different-sized rails - some with or without numbers. The pictures were tiny, so I was squinting to see which way around the rails went (turns out they were all printed so the writing was always facing the right way up).
The door for the computer stack had hinges - I'd never put any of those on anything either.
This thing is all pressboard, so I tried to be really careful with the automatic screwdriver, because the board just turns to powder if you strip the screws. I didn't strip any.
I got all the rails put on correctly, the door works great with its hinge, and I managed to get the nails & screws all flush so nothing is scraping or catching on anything when you move it.
I put the handles on the drawers perpendicular - not horizontal. Whoops. My bad.