You use estoy for temporary states, things that can change
I am awake is Estoy despierto
she is sad is Esta triste
You are in love is Estas enamorado
I am > estoy
you are > estas (singular casual) esta (singular formal)
(s)he is > esta
we are > estamos
you are & they are > estan
Soy is something that defines you and is not likely to change
I am tall is Soy alto
You are a man is Eres hombre
I am > soy
you are > eres (singular casual) es (singular formal)
(s)he is > es
we are > somos
you are & they are > son
As a note you can use both with things like happiness. I don't know why but you can translate I am happy as Soy feliz or Estoy feliz and it's correct
And I don't think we need the auxiliary verbs do and does in Spanish, just as verbs
Do and make in Spanish translate to the verb hacer