What is the difference between "ser" and "estar"and when to use them

Spanish has two verbs "to be" and that is "ser" and "estar"
The difference:
"Ser" Used with nouns, pronoun or infinitive e.g. Es una lengua, Quien estaba al telefono? Lo importante is firmar identity and define such as your nationality e.g. soy español/aownership and origin of someone/something e.g. la comida es tuya, la puerta es de madera time e.g. sin las siete events (time and location) e.g. la reunion sera el dia 2 de febrero passive sentences e.g. la novela de Don Quijote fue escrita por Cervantes
"Estar"location current state of affairs: illness, mood e.g. estoy cansada/owith the gerund (in the present tense) e.g está lloviendo Adjectives (which indicate a change in norm appearance) (viejo, contenta) e.g. ¡Qué viejo está! (he looks old compared to usual) d ¡Estas muy contenta hoy, Gloria! (she looks unusually happy for her)used with the past participle e.g. el libro estaba escrito en inglés


Present tense "ser" and "estar"ser: yo soy, tu eres, el/ella/usted es, nosotros somos, vosotros sois, ellos/ellas son estar: yo estoy, tu estas, el/ella/usted está, nosotros estamos, vosotros estaís, ellos/ellas están

Intermediate level :Other tenses to be discussed

Advanced level : Adjectives change meaning depending on the verb used aburrido with "estar" means bored but with "ser" it means boring bueno with "estar" means delicious but with "ser" it means goodcansada with "estar" means tired but with "ser" it means tiring listo with "estar" means ready but with "ser" it means clever