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This is a concept that is not completely unknown to us English speakers. When referring to a ship, for example, we often call the ship “she” even though a ship is an inanimate object. But for the most part, we don’t deal with the concept of gender when referring to things other than animals and people.
Spanish is different. Almost every noun (remember  person, place, or thing?) is either male or female. Sometimes a noun can be neuter, but generally it is either masculine or feminine.
What are the implications of this?? It makes a big difference when considering which article to use in reference to the noun. 
Articles
An article is one of the small words that come in front of the noun to indicate whether it is definite. Consider the following two sentences:
I want the job.
I want a job.
Both a and the are articles. But their presence in the sentences conveys two completely different meanings. The first sentence refers to a job which really exists. This is a definite article, as there is a specific job the speaker is talking about. The job in the second sentence may or may not exist. In this case, a is an indefinite article.
So with Spanish we use the articles just like we do in English:

Telling if a word is masculine or feminine
This is not 100% foolproof. However, if a word ends in o, e, or a consonant, it is generally masculine. If a word ends in a, it is generally feminine. However, there are myriad exceptions to this rule, so be careful
Examples
The book             el libro
The door              la puerta
A boy                    un niño
A basket              una cesta
The pesos           los pesos
The burgers        las hamburguesas
Some clowns     unos payasos
Some bottles     unas botellas