We use to in order to express movement toward a place.
They were driving to work together.
She's going to the dentist's office this morning.
Toward and towards are also helpful prepositions to express movement. These are simply variant spellings of the same word; use whichever sounds better to you.
We're moving toward the light.
This is a big step towards the project's completion.
With the words home, downtown, uptown, inside, outside, downstairs, upstairs, we use no preposition.