Help please, I'm confused. I still don't know when to use est or es. How do they differ?
It depends on which "person" the subject is. Est is used when the subject is the third person (he, she, it), while es is used for the second person (you). Both apply in the singular only. I hope that helps!
you have to use "es" only with "tu" (you)
you have to use when you're using est with "il, elle, on, c'est " ...
ex) tu es mon aime.
il est vieux.
elle est jolie.
on est partis.
so, you can think that "es=are" , "est=is"
Handy verb conjugation reference: