The portuguese verbs 'ser' and 'estar' both translate into the english verb 'to be'. However, the two are not interchangeable.
'Ser' is used in situation where you want to describe a permanent state, often something related to identity.
'Estar' on the otherhand describes a current state, or the way someone/something exists in that moment.
They are conjugated as follows:
Ser - eu sou, tu és, ela/ele/você é, nós somos, vós sois, elas/eles/vocês são
Estar - eu estou, tu estás, ela/ele/você está, nós estamos, vós estais, elas/eles/vocês estão