Hi Joan,
I believe that's from the deciphered message. Did you do this yet (still on day 5):
German envelope: Read the letter inside on how it was collected. There is also the star sheet and the coded text message.
Look at the coded text. Combine the cypher code keys with the coded-cyphered text and get a deciphered message.
Read the translated message. There are 5 books that are needed to be found.