Ser means to be.  Remember that in Spanish, a verb has different forms or endings which tell you what the subject is.  Below is a review of the conjugation of ser .   

Since ser means to be, it can be used with adjectives to describe nouns (people, places, or things).

The proper word order for a simple sentence using ser and adjectives is:
             (subject pronoun) + ser + adjectives
The subject pronoun is given in parentheses, because it can be implied or stated.
The verb ser must be conjugated to agree with the subject.
The adjectives must agree in number and gender with the subject.

In English, we use personal subject pronouns out of necessity, because most sentences without subject nouns would not make sense. In Spanish, the verb form often indicates who the subject of a sentence is.  Therefore, one can properly leave out the subject pronoun.  The pronouns are used primarily for clarity or emphasis.

In Spanish, most adjectives change form, depending upon whether the word they modify is masculine or feminine.  Notice the difference between "The boy is tall. - El chico es alto." and "The girl is tall. - La chica es alta."   

To make a sentence negative, insert no before the verb.  No es moreno.  If a sentence contains a subject noun or pronoun, the no is placed between the subject and verb.  Marisa no es bonita.