Differences between ES and EST?
es is used when using you (informal) So if you are saying 'you are', it is 'tu es' (unless you are talking formally in which case it is (Vous êtes) Think of it as the equivalent of 'are' when you are talking to one person who you know well
est is basically the French equivalent of the English word 'is' so you use it if you are saying 'he is' (Il est) or 'she is' (elle est)
I recommend you learn the conjugations of the verb être (to be) if you haven't already as this will help you a lot:
Je suis - I am
Tu es - You are
Il/Elle est - He/She is
Nous sommes - We are
Vous êtes - You (plural or formal) are
Ils/Elles sont - They are
Hope this helps!
EDIT: Changed informal to formal :)
Just started learning again. 11% through and this was a huge confusion for me. Thanks!!!