Instructions: Put the top of the hook into the slot on the main piece flat side up. Screw in two screws a bit more than 3cm apart. Align the holes on the top of the main piece with the screws and insert the main piece into the screws, next slide the main piece back to secure it into place. If it is not tight enough you can tighten the screws through the holes in the bottom. 

Hope you like it!