Dutch prepositions with place meanings require specific attention because they do not always match English equivalents. Op (on a surface, also at certain locations): op tafel (on the table), op de grond (on the ground), op school (at school), op het werk (at work), op het station (at the station). In (inside, within a space or area): in de keuken (in the kitchen), in de stad (in the city), in het bos (in the forest).
Aan (attached to, at a boundary): aan de muur (on the wall — attached/hanging), aan de rivier (at the river), aan tafel zitten (to sit at the table), aan de kust (on the coast). Bij (near, at someone’s place, with a company): bij de deur (near the door), bij Jan thuis (at Jan’s home), bij Albert Heijn werken (to work at Albert Heijn). Naast (next to), tegenover (opposite), achter (behind), voor (in front of), boven (above), onder (under/below).
The distinction between op de muur and aan de muur is characteristically Dutch. Op de muur = sitting or standing on top of the wall. Aan de muur = hanging against the wall. This distinction between surface contact and vertical attachment has no direct parallel in English. Similarly: op de fiets (on the bike — mounted) vs. met de fiets (by bike — as transport). These fine distinctions are what mark a fluent Dutch speaker — they come naturally with extended exposure and use.