Estar is the infinitive form, notice that because ends with
-ar (which indicates first conjugation).
Your sentences has a few mistakes, first of all:
Los libros está a la derecha de el escritorio.
Libros are the subject of the sentence, so there are in the plural form (
libro is singular and
libros plural), this indicates the verb to stay in plural form. The second little mistake is to contract
de + el in
del Like this:
Los libros están a la derecha del escritorio.
In the second sentence, the subject is
casa (one, so it's singular). The verb remains in the singular form:
Mi casa está en una zona muy bonita.
Notice that I've also corrected the verb tense (as I said, estar is infinitive). This is a normal mistake when anybody learns spanish. Verbal tenses are much different than english and it's difficult to get used and involved in that.
I'll add you some extra information in order to try to explain the verbal tenses better:
Every verb (except the irregular ones) follows the following rules:
1st conjugation (for example cantar(to sing) in present:
1st person of singular: Yo canto (I sing)
2nd person of singular: Tu cantas (You sings)
3r person of singular: El/Ella canta (He/She sings)
1st person of plural: Nosotros cantamos (We sing)
2nd person of plural: Vosotros cantáis (You sing)
3r person of plural: Ellos/Ellas cantan (They sing)
With this rule you can conjugate every regular verb tense, because all of them follow the same structure (second conjugations are the ones which infinitive ends with
-er and the third conjugation with
Hope this paragraph has been useful for you and If you need some extra information just ask and I will edit this answer.
Edit: There's no difference between
está refered to persons and refered in places or locations if the verb
estar has the meaning of position (as
to stay). If you are using
estar as a emotional or to transmit feelings (
to be) of course there is a big difference and you cannot use
estar in places. In your case you are using
estar in the meaning of location. The person is to the right or to the left and the house also can be located to the right or to the left.
You cannot use: La casa está triste (The house is sad)/Estoy triste (I'm sad)
But you can use: La casa está a la derecha (The house is in the right side)/Mi amigo está triste (My friend is sad)