"Ser" is used to describe permanent attributes, for example: personal descriptions, someone's profession, the origin of a person or object. etc.Examples:María es alta y delgada (María is tall and thin)Juan es cocinero (Juan is a chef)Esta café es de Colombia.
"Estar" is used to describe more temporary attributes, for example: the location of an object or place, the condition of something, or emotions etc.Examples:La cuchara está sobre la mesa (the spoon is on the table)Estabas muy cansado ayer (you were very tired yesterday)My equipo de fútbol perdió ayer, y por eso estoy triste (My football team lost yesterday, and because of this I'm sad)
Note that getting the difference is important, as the two different verbs can change the meaning of a phrase if used wrongly:Examples:Estoy aburrido (I am bored) vs Soy aburrido (I am a boring person)El mango es verde (the mango is green) vs El mango está Verde (The mango is unripe)