Argentina and Uruguay (and I think also Paraguay) use the "Vos", and is used as "Tú" would be used, you just need to learn the whole range of verb conjugations that correspond to this personal pronoun which only changes the accent of those verbs that correspond to "Tú" in the present tense only, for example:
For regular verbs in present tense
Verbs that end in "ar": "Vos hablás"
Verbs that end in "er": "Vos comés"
Verbs that end in "ir": "Vos vivís"
etc.
Hope this helps,
JD