Learn French: À quelle heure fermez-vous le bureau ? - At what time do you close the office?

Use À quelle heure when you want to know a specific time on the clock, like 5:00 PM. Use Quand (when) for a general time, day, or date, like tomorrow or next week. If you translate it literally, À quelle heure means "At which hour".

Do I have to put À at the very beginning of the question?

Yes! In English we often drop the "at" and just ask "What time do you close?", but in French, the preposition À (at) almost always stays glued to the beginning of the question word. You are literally asking "At what time...?".

Why are the verb and pronoun swapped and joined by a hyphen in fermez-vous?

This is called inversion, which is a formal way to ask a question in French. Instead of saying vous fermez (you close), you flip the words to fermez-vous (close you?) and connect them with a hyphen.

Does le bureau mean "the desk" or "the office"?

It can mean both! You have to figure it out from the context. Here, a business closing "the office" at the end of the day makes much more sense than closing "the desk".