Rob
Forum Moderator
There are general tutorials in the Help system (click on Help in Fluent) and I'd suggest doing some of the courses from the top of the page. They'll cover some of the fluids topics and terms.
From there you'll need to decide what exactly you're trying to model, and then will need to figure out how to get the geometry built etc. CFD can be used for coastal modelling, but given the domain sizes etc it's not necessarily the best choice.