Use am for I. Use is for he, she and it. Use are for you, we and they. We can contract the verb, especially when we're speaking.

I am tall. = I'm tall.
You are my friend. = You're my friend.
My mum is a doctor. = My mum's a doctor.
We are doctors. = We're doctors.
They are Egyptian. = They're Egyptian.

For negatives, use not.

I am not nine years old! = I'm not nine years old!
She is not a teacher. = She's not a teacher. = She isn't a teacher.
They are not English. = They're not English. = They aren't English.

For questions, change the order of am, is or are and the person.

Are you Brazilian? Yes, I am.
Are they students? No, they're not.
Where is your brother?

We can watch Usyk`s fight on Youtube.

They can go out with their friends every Friday.