"How are you, Carmen?"
Translation:¿Cómo estás, Carmen?
First: When you use usted (formal >you<) it's está, because it's 3rd person singular. Estás is 2nd person singular (informal >you<).
Second: "Usted" is used when you don't know the person or the person is older or your boss or sth. When you're on first name basis it's a very good indicator to use the 2nd person singular
The verb ser (which es is a form of) means "to be" and it is used more permanently like to say where you live, your gender, your name, etc. But the verb estar (which está is a form of) also means "to be" but it is used more currently like to say how you currently feel or what you are currently doing
Here is what I found:
Cómo te va The easiest translation of "cómo te va" is "how is it going".
"Cómo te va" is quite similar in meaning to "cómo estás", it's just a bit more informal and colloquial. "Cómo te va" can also be used to ask about more specific events, whereas "cómo estás" is just for a casual greeting or to query someone's wellbeing in that moment. This article explains the difference further and has some useful examples of when you'd use each one. However, in most situations they'd be interchangeable.
Cómo te vas/Cómo se va "Cómo te vas" and "cómo se va" are essentially the same, they only differ in terms of formality (or who you're talking to).
Cómo te vas - 2nd person singular in an informal setting
Cómo se va - 2nd person singular in a formal setting OR third person singular
That being said, it's not a very common expression and would only be used if you're talking specifically about the manner in which someone is leaving. It would be more natural to use the verb "ir" (without the reflexive pronoun) to ask how someone is getting somewehere: "Cómo vas a la escuela hoy". Even more natural sounding would be to use the verb "llegar". Like someone wrote above, "como se va" can also mean "how does one go/get to X place".