Why study the Psalms: 3 reasons for me. First, the dialogue between the Father and the Son in the Epistle to the Hebrews is comprised of words from the Psalms. What was that first-century preacher doing? Second, structure is an intriguing study. Third, can one communicate across 2500 years with an ancient mind?
My first diagrams on Hebrews are here - there are about 7 diagrams including a structural overview which I derived from the work of Albert Vanhoye.