I need help with italian! I can teach you croatian if you want.

  Ok, so, here's the deal. I'm learning italian in school, and I've started this year. And my final exams are coming soon, and I need someone to help me just a little bit. Nothing too much. I just need explanation why, when and how are some things used, for example prepositions (e.g. di, a, in etc.) Thank you :)