The first monument on Ybiza island has four bucket like squares in the middle and lots of bricks in the ground nearby. Ihave put one block in each of the squares but it has not activated anything. What are you supposed to do here? It looks like buttons on top of the taller pillars but they do nothing either.
The pillars are the clue. The button like notches on top represent the number of stones you should out in each of the squares. So if it has one notch on top of the pillar, the nearest Square on top of the monument needs one stone placed inside it. Once the correct number have been placed in each of the squares, the monument will open up.