Prepotion of the place

On = En (sobre)
In = En (dentro)
Betweem = Entre
Behind = Detras
Beside = A lado
Nexto to = Al lado-Cercano a
Under = Debajo
In front of = Enfrente de

Where is the clock? It's on the wall, beside the map

Where is the blackboard? It's on the wall, in front of the clock

Where is the desk? It's on the floor, under the study sheet

Where is the book? Its' on the desk, nexto to the sheet

Where is the sheet? It's on the desk, betwee the book and the chalk