Question

não estou entendendo muito o verbo to be

Answer 1

Ue, o verbo to be é o pronome:

 - PRESENTE- 
I                 AM
You            ARE
He,She/It    IS
You            ARE
They          ARE

-PASSADO-
I                  WAS
You             WERE
He/she/ it    WAS
We              WERE
You             WERE
They           WERE

Ex.: I AM happy / I WAS not happy

Answer 2

simples,
i am
you are
he is
she is
it is
we are
they are

forma negativa, só adicione o "not"
ex: i am not./ you are not

forma interrogativa inverta o verbo principal.
ex: am i?/ are you?/ is she?