There are two ways to say "to be" in Spanish. One is Ser. The other is Estar. Here are some links to learn more about Ser, and you can also explore the difference between Ser and Estar.
The verb SER means "to be". We use it to describe things and people, to tell time, to say where someone is from, etc. The conjugations are:
soy - eres - es - somos - son.
Use the resources and your textbook to learn more:
Online activities from the Exprésate textbook
Book 2 Chapter 2 p. 54 (Review of Ser with adjectives of nationality)
Practice with the Present tense of the verb SER - Review with nationality
Grammar explanations with self-correcting exercises
Ser - Present tense conjugations