Tú and usted both mean you. So what's the difference?
Tú is used in friendly conversations.
Meanwhile, usted is used in more formal interactions.
Remember to use estar to describe things that are only temporarily true, like the location of people and things.
You would also use estoy, estás, or está to talk about how people are feeling or doing.
Use ser for more permanent descriptions, like explaining what someone is like.
You would also use soy, eres, or es to say where people are from.