A preposition tells us where something is in time or space.

Some English prepositions: in, out, over, under, before, after, during, through

Porcus sub aqua est. = The pig is under water.

Equus per villam currit. = The horse runs through the house.

Femina in taberna stat. = A woman stands in the shop.

Prepositions: sub = under. Per = through.  In = in/on