Articles are basically adjectives. They modify nouns. There are three articles namely a, an, and the. The is used to refer to something specific or particular. It is called a definite article. A and an refer to something non-specific or non-particular. They are called indefinite articles.
* Please give me the newspaper. In this sentence, the speaker refers to only one news paper.
* Please give me a newspaper. In this sentence, there are many news papers. The speaker doesn’t care what newspaper.
* An amateur chess player won the world championship match. In this sentence, an amateur player is a non-specific player; however, the world championship match is a specific championship game.