Yea I was confused with these two verbs as well...
Both "era" and "fue" are conjugation of the verb: ser - to be.
In the past tense, "ser" is conjugated as:
yo fui
tu fuiste
ud fue
nosotros fuimos
uds fuieron
In imperfect tense, "ser" is conjugated as:
yo era
tu eras
ud era
nosotros éramos
uds eran
both past tense and imperfect tense describe actions in the past, but "fue" is used to describe exact time of a specific event while "era" is used to describe non-specific event in the past; it is literally translated as "used to be".
For example, I was at the library 3'o clock yesterday -> yo fue a la biblioteca a las tres ayer.
When I was ten years old, I lived in Spain -> cuando era diez anos, vivia en Espana.
Another twist to this, fue is also a conjugation of the verb "ir"