What's the difference between "Anda" and "Kamu"?
'Anda' is formal, and 'kamu' is informal.
'Anda' is used with strangers who are older than you. However, if someone is old enough to be your mum or dad (or older), you would use 'bu' or 'pak' to refer to them.
'Kamu' is used between individuals of the same age or younger. It is usually used between friends.
Also, bare in mind, Indonesians often use someone's name instead of a variant 'you'. E.g. I've been asked "Jesse mau ke mana?".
From my understanding, there isn't much of a difference. The completed forms are just slightly more formal. For example, you would say 'Bapak Presiden'.
Formality is an important aspect of Indonesian and Indonesian cultures. Even at university, I still refer to my lecturers for Indonesian as 'Bu' and 'Pak'.
I get the impression that Anda is rarely used in day-to-day speech. You kinda have to learn whether someone is a Bu, or a Mas or a Daeng or a Mba' or an Om and use that. If your experience is anything like mine, you'll find that whenever you're introduced to someone new, someone will say "This is Om Kimo" or whatever and you can go from there.
To make things easier, pronouns can be dropped pretty often in Indonesian, hence "Mau ke mana" rather than "Kamu mau ke mana?" etc so you can probably get away without knowing how to address someone in lots of situations.