Marine mammals spend most of their time underwater which sometimes makes it difficult to detect them from the surface. At the same time, most cetaceans (toothed and baleen whales) produce a variety of sounds underwater and since sound travels easily in water, these sounds can normally be picked up even at distances beyond those of visual detection. Several studies have shown that the analysis of underwater sound recordings can complement the existing research efforts to assess the presence and distribution of cetacean species in the Caribbean waters and elsewhere. We hope the system will be easy to use even by untrained personnel and robust enough to withstand the strain of being used in the marine environment. This user’s guide is intended to serve as a practical illustrated step by step users guide useful information in addition to the manual provided with every recording system.