To hang the pictures, you need to:
1. Find a couple round head screws
2. Measure the width between the holes (pick the two in the middle)
3. Fix the screws into the wall with about 1 cm sticking out. Make sure the screws are aligned both horizontally and vertically
4. Once you have fixed the screws, just hang the holes on the heads of the screws. It will sit naturally on its own.