Polish uses different endings for movement and for location. With do ("to") the place takes the genitive ending, usually -a or -u; with w or na meaning "in/at" the place takes the locative ending, usually -e or -u. Choose the preposition first, then the matching ending.
Examples
- Jadę do Krakowa.
- I'm going to Kraków.
- Mieszkam w Krakowie.
- I live in Kraków.
- Idziemy na dworzec.
- We're going to the station.
- Czekam na dworcu.
- I'm waiting at the station.
The mistake to avoid
Using w with a destination — "idę w sklep" is wrong; movement needs do sklepu, and w sklepie means you're already there.
Where this fits in
Travel & directions, Polish A2: Get around in a Polish-speaking city: take transport, ask the way, check into a hotel, and buy a ticket.