[dizzymommy]

If you're on the quest I'm thinking you are on you need to go into the building at thieves den and search the table.

As for the Navy Guard if the quest simply states from A Navy Guard and does not mention a specific place then you can get that from anyone Navy Guard in the game. Navy Guards are the ones in the red and white jackets. eg. Cadet, guard, veteran etc. A good place to go is the Fort Charles (which is up the hill to the left if you are standing on beach facing buildings) on Port Royal.

Good luck. If you need help most just ask for it while playing the game. Most people are pretty friendly and will tell you where you need to go.