Hello Piggy,
here are 12 rules of using "the". I hope that this will help you
1.) Used before singular or plural nouns and noun phrases that denote particular, specified persons or things: the baby; the dress I wore.
2.) Used before a noun, and generally stressed, to emphasize one of a group or type as the most outstanding or prominent: considered Lake Shore Drive to be the neighborhood to live in these days.
3.) Used to indicate uniqueness: the Prince of Wales; the moon.
4.) Used before nouns that designate natural phenomena or points of the compass: the weather; a wind from the south.
5.) Used as the equivalent of a possessive adjective before names of some parts of the body: grab him by the neck; an infection of the hand.
6.) Used before a noun specifying a field of endeavor: the law; the film industry; the stage.
7.) Used before a proper name, as of a monument or ship: the Alamo; the Titanic.
8.) Used before the plural form of a numeral denoting a specific decade of a century or of a life span: rural life in the Thirties.
9.) Used before a singular noun indicating that the noun is generic: The wolf is an endangered species.
10.) Used before an adjective extending it to signify a class and giving it the function of a noun: the rich; the dead; the homeless.
11.) Used before an absolute adjective: the best we can offer.
11.) Used before a present participle, signifying the action in the abstract: the weaving of rugs.
12.) Used before a noun with the force of
per: cherries at $1.50 the box.
Best regards,
Dany