"It is a restaurant."
Translation:Det er en restaurant.
Restauranten = the restaurant. En restaurant = a restaurant. If it's indefinite (a restaurant) you put the en before the word. If it's definite (the restaurant) you put the en at the end of the word. Jeg ser restauranten. You would say that if you had discussed a location beforehand.
So if det is neuter and den is masculine, why is it "det er en restaurant", if restaurant is masculine?
Cheers! You answered both my questions, you lovely and knowledgeable human being.