"Let's distinguish between origin, location, and "to take place." To describe origin, or where something is from, use ser. To describe location, or where something is located right now, use estar. To tell where an event is taking place, use ser.
Mónica es de España. (origin)
Mónica está en Venezuela. (location)
La fiesta es en la casa de Mónica. (taking place)
When a noun follows the verb, use ser
When an adjective follows the verb, decide between "essence" and "condition"
To tell where somethin…