The difference is basically the verbs. "Ser" is "to be" in a permanent sense, "estar" is "to be" in a temporary sense.
Ella está enferma (she was ill) temporary
Ella es profesora (she is a teacher) permanent.
Ella ha sido nombrada miembro honoraria (she has been given the title of honourary member) permanent.
Ella ha estado en Uruguay 4 veces (she has been to Uruguay 4 times) temporary.
I hope this helps.