¡Chicas! ¿Qué tal? = (girls), how war you?
¡Bien! = Fine!
¿Como estáis? = how are you? (qué tal=> literal: how this; como estáis=> how are you)
qué tal is only used this way. It is actually the abbreviation of qué tal estáis, but in the course of history nothing remained but qué tal. No need to think about it. It is fixed expression and con only used in this context.
Muy bien = Very fine.
Menuda fiesta que hay dentro. Es increíble. = It's a super party here inside. It's incredible.
me encanta. Lo que pasa es que no se oye nada.= I like it. But it's hard to understand each other. (literal: It succeeds that nothing can be heard.)
¿Cómo? = How?
Que no se oye nada. ¿Te gusta la fiesta? = It's hard to understand each other. Do you like the party?
Sí = Yes
A mi tambíen. Han venido todos los primos = I like it as well. All cousins have come.
han venido: pasado perfecto
No te oigo = I can't here you.
Todos los primos y sobrinos = All cousins and nephews
¿Los primos? = The cousins?
Sí, los primos y los sobrinos. Están todos dentro en la fiesta. Es enorme, está llenísima
= Yes the cousins and the nephews. All of them are on the party. It's enormous, a lot of people.
¿Tu primo es enorme? = Your cousin is enormous?
No, mi primo no. Los primos, todos. = Nein, nicht mein Cousin. Die Cousins, alle.
¿Todos los primos enormes...? = Alle Cousins sind enorm?
No! No me entiendes...= No. You don't understand me.!
¿Qué dice? = What does he say?
¿No me oyes? Los primos que han venido. = You don't understand me? The cousins, the cousins has come.
Somos mucha gente, muchos. = There are a lot of people, a lot.
Vale! Después los conozco. = All right, I will know them later.
¿Que ya los conoces? = Do you know them already?
Vamos a brindar! Que no te escucho. = Let's clink. I can't hear you.
Vale! = Ok!
Pues pasarlo bien, ¿eh? = Have fun, ok? (literal: to pass well, ehß)
This is very colloquial. Actually it should be 'qué lo paséis bien' or something like that. Normally spanish uses the congiuntive in this context. But the language of youngsters and you young adult doesn't fit always with the standard grammar. These young adults are spanish native speakers. The constructions are therefore common, although they not always can be really explained.
Vale! =Alright! (Literal: It's valid)
Vuelvo dentro... = I go in again..