So I have read the prologue and a bit of chapter one and want to know if the question's I have are normal or if I need to go back to Brandon Sanderson books

1. Is there an explanation on how the yearing works? Burn's sleep?
2. Is the place were the prologue takes place on the map at the beginning of the book? Wanted to get a better visual of everything.
3. Why does the commander say "Hope the emperor knows what it means" when he learns that She's* (aren't emperors male? might of just misunderstood here) is changing her name to Laseen, does the meaning of a name matter?
4. Ganoes says Napan teachs him but is frightened when that lady shows up who is Napan???
5. So this Napan lady is a witch? who is in charge of the other witches and the commander is commanding an army of young sorcerers??? Why doesn't the commander kill the enemy napan there?