To talk about where something is located or where something happens you can use 在 zài followed by a location.
The expression 在 + location normally appears before the verb. Example:
我在英国工作。 Wǒ zài Yīngguó gōngzuò. I work in Britain.
Similarly, to say that something originates from somwhere you can use 从 cóng followed by a location.
The expression 从 + location appears before the verb. Example:
你从哪里来? Nǐ cóng nǎli lái? (Literally, You from where come?)
我从北京来。 Wǒ cóng Běijīng lái. (Literally, I from Beijing come.)