How do you turn proper nouns into proper adjective

Proper nouns are nouns that name specific people, places, things, or ideas. Think of proper as meaning specific.

America, English, Paris
Notice that proper nouns always begin with a capital letter.

Proper adjectives are adjectives that are formed from proper nouns. Most of them identify people, places, languages, or groups.

American cars, English grammar, Parisian scarf
Notice that these adjectives are still performing the job of an adjective: They are all describing nouns. Also, notice that they all begin with a capital letter.