Grammar

The use of "man" in impersonal sentences

"man" is an impersonal pronoun that substitutes a noun. It is used to signify a person or several people, but no one in particular. So it is often used to express generalizations.

Example:
Hier darf man nicht Fahrrad fahren. (= That applies to everyone.)

"man" is always used in the nominative and the singular, even when it applies to "everyone". There is no plural form of "man".

"man" vs. "Mann"

Don't confuse "man", the impersonal pronoun, with the noun "Mann".
Written with one "n", "man" signifies people in general, including females.
"Mann" spelled with "nn" is the word for an adult male.