Learn Swedish: Man får inte röka här. - You must not smoke here.

In Swedish, man is a generic pronoun used to talk about people in general, rules, or common habits. While it translates literally to the formal English "one", native English speakers almost always use "you" for this kind of general rule.

The translation says "must not", but doesn't får usually mean "to get" or "may"?

Yes! When used as a helper verb alongside another verb, får means "to be allowed to" or "may". Therefore, får inte literally means "is not allowed to" or "may not". In natural English, we usually express this kind of strict rule with "must not".

Could I use måste inte instead of får inte to say "must not"?

No, that is a very common trap! In Swedish, måste inte means "do not have to", meaning there is no obligation to do it, but you still can if you want. If you want to say that something is strictly forbidden, you always use får inte.

Why does inte go right in the middle of får and röka?

In a standard Swedish main clause, the word inte must come directly after the first verb, which is får here. The second verb in the sentence, röka, gets pushed to after the adverb.