The differences between ser and estar are considered one of the most difficult concepts to nonnative speakers. Both ser and estar translate into English as to be, but they both express different ideas. These differences may be generalized so that ser expresses nature and estar expresses state. One easy way to remember is: ser is generally for permanent things; estar is generally for things that are temporary.
As a general rule, use the verb "ser" for permanent things, things that are always true.
1.- Nationality - use the verb "ser" in order to talk about the place of birth or origin of people.
Yo soy español.
I am Spanish.
Los padres de Marcos son de Brasil, pero crecieron en Portugal.
Marcos's parents are form Brazil, but they grew up in Portugal.
Nosotros somos de Málaga, pero vivimos en Sevilla.
We are from Malaga, but we live in Seville.
2.- Time and date - When telling the time always use a plural form, except for one.
As a general rule, use the verb "ser" for permanent things, things that are always true.
Uses of Ser
1.- Nationality - use the verb "ser" in order to talk about the place of birth or origin of people.
Yo soy español.
I am Spanish.
Los padres de Marcos son de Brasil, pero crecieron en Portugal.
Marcos's parents are form Brazil, but they grew up in Portugal.
Nosotros somos de Málaga, pero vivimos en Sevilla.
We are from Malaga, but we live in Seville.
2.- Time and date - When telling the time always use a plural form, except for one.