Hi !
Caroline : Bonjour Fred
Frédéric : Salut Caroline
Caroline : Voici Sophie
Fred : Qui est-ce ? (= Who is she ?)
Caroline : C'est une élève. Elle est de France.
Fred : Ok, merci.
Comment s'appelle la fille = What's the name of this girl (the name, Sophie, has just been given
Je ne sais pas = I don't know (no question before)
ça va bien , =:Are you alright ?/ are you doing well (a question but doesn't suit with the text)
qui est-ce ? = Who is she ?
hope this helps !