"The boy has books."
Translation:Le garçon a des livres.
Articles (e.g. "the" or "a") provide context for a noun. In English, articles may be omitted, but French nouns almost always have an article.
Indefinite articles ("a"/"an"/"one") are used for countable nouns that are unspecified or unknown to the speakers. In French they are gender specific → un and une (masculine and feminine respectively).
Unlike English, the French indefinite article has a plural → des (masc fem).
Le garçon a un livre → The boy has a book
Le garçon a des livres → The boy has books.
There are those who like to think of des as some but its addition to most sentences is superfluous. For example, there is no need to write The boy has some books.
No. avez is the 2nd person plural present indicative conjugation of avoir.
"The boy" = "he"
Le garçon = il. This sentence is written in the 3rd person singular present indicative so requires the avoir conjugation a. See the conjugations of avoir here:
They are all conjugations of the verb avoir (to have) It is like in English when you say I "have" and he/she "has." the words mean the same thing but depending about whom you're speaking, the verb changes form. J'ai - I have Tu a - You have (when speaking to a friend or family member) Il / Elle as - He / she has Nous avons - We have Vous avez - You have (When being polite or speaking to more than one person) Ils / Elles ont - They have (Ils is talking about a group of all men or men and women and Elles is talking about a group of only women)