Prepositions of Place: at, in, on
In general, we use:
at for a POINT
in for an ENCLOSED SPACE
on for a SURFACE
at
POINT
in
ENCLOSED SPACE
on
SURFACE
at the corner
in the garden
on the wall
at the bus stop
in London
on the ceiling
at the door
in France
on the door
at the top of the page
in a box
on the cover
at the end of the road
in my pocket
on the floor
at the