1. First you need to find the book and make sure it was purchased, check you purchase history.
2. Click on the transaction/book and then click 'send to' and choose your daughter's device
3. Do this for each of the books you purchased and are missing on her device
4. If you don't see her kindle, register it on your account and then complete steps 1-3
5. Next time you purchase a book confirm the device in the drop down box before you click to pay for the item.
Hope this helps you.