When talking about the verb “to be” in Spanish, there are two different ways to make this expression, so it can be a little tricky for a non-native speaker to understand the differences between them.
And if you want the things a little more complicated there is a Spanish impersonal verb that can also be translated as to be, and is haber – hay, and It’s used to say “there is/are”.
In the case of soy and estar, this two verbs are irregular, which means that they change they form when are use with different nouns, for example:
Yo soy, tú eres, él/ella es, eso es, ellos son, nosotros somos, ustedes son.
Yo estoy, tú estás, él/ella está, eso está, nosotros estamos, ustedes están.
Every one of these forms of the verbs ser and estar means the same but are structured with different nouns.
The most important thing here is that you can be able to identify when to use ser and when to use estar, for that you need to understand the differences between their meanings.
Ser must be used when you are identifying or describing the noun, like picturing the person or thing you want to make reference. Also apply when talking about a job or the nationality, or when talking about something belonging. For example:
Yo soy el más inteligente, ella es la más linda, ellos son camareros, ese cuaderno es mío.
On the other hand, estar is mostly used when you want to make reference to the geographic location of something or someone, when someone is doing something, or to express feeling, states, conditions or something temporary. For example:
Estoy en la panadería, ella está en casa, eso está sobre la mesa, ellos están cantando.
In the case of haber, is used to inform the existence of something in this moment, for example:
Hay pan, hay muchas personas, hay un evento.