A few hints:

There is a little treasure map on the wall next to the door, but it is a bit vague:

1 is hidden in some plants on red side, near the entrance to the soldier statue.
2 is in the ocean, close to a silly fish.
3 is hidden in blu hotel next to a pizza face painting.
4 is somewhere next to the receptionist on the wall in red hotel
5 is by the ferris wheel somewhere
6 is between both hotels, somewhere high up..