Syntax is the study of how forms combine into sentences. Once the endings are known, the question becomes what they do: why a noun stands in the accusative, what a subjunctive expresses, how a long period holds together. Because Latin word order is free, the endings carry the grammar, and syntax is where they are put to work, for example in Brūtus Caesarem amat.
The forms themselves are set out in Morphology, and the reference tables are in Resources.