"Hello, where are you from?"
Translation:Halo, kamu dari mana?
"Dari mana kamu?" is also accepted. "Dari mana" is the interogative word, dari = from, mana = where. So, the interrogative "dari mana" is "from where" and means in English "where from".
Kamu dari mana (literally): You (are) from-where? Dari mana kamu: From-where you (are)?
The second one places the interogative word (dari mana) at the begining, I believe it's more formal.
"Kau" is not a typing error. It's another form for "kamu", it's more informal than "kamu".
You can use "kau" or "engkau" very informally, with friends.
Formality (for one person):
Anda > kamu > kau.
If you speak French or Spanish, "Anda" is equivalent to the French polite vous, or the Spanish usted.
And there's also kalian, meaning a plural you.