Three quick questions to find out whether your trip is authorised, which OFAC category covers it, and what records you need to keep.
Authorising regulation: 31 CFR §515.560 — General travel framework
Tourism per se is explicitly excluded from the OFAC general-license framework. U.S. citizens, U.S. permanent residents, and U.S.-resident persons may not travel to Cuba for pure leisure / beach / resort purposes. Engaging in tourist transactions in Cuba violates the CACR and exposes the traveller to civil and criminal penalties under the International Emergency Economic Powers Act (IEEPA) and the Trading With the Enemy Act.