1. Ne znam JE LI DAN pročitao knjigu.
= I don't know whether Dan read the book.
2. Ne znam kada JE Dan pročitao knjigu.
= I don't know when Dan read the book.
3. Ne znam gdje JE Dan pročitao knjigu.
= I don't know where Dan read the book.
4. Ne znam zašto JE Dan pročitao knjigu.
= I don't know why Dan read the book.
5. Ne znam kako JE Dan pročitao knjigu.
= I don't know how Dan read the book.
6. Ne znam kto je pročitao knjigu.
= I don't know who read the book.
Just like in the English language, after "when" , "where", "when", "how", "why" always comes the verb "to be" then the personal pronoun.
Follow the Ivana's instructions cause she explained you really good.