Many people find the Psalms confusing but there is order to them and there are important messages for us in them. The Psalms can be looked at as the hymnbook of the Israelites. They are poems intended for public presentation, usually accompanied by music.
Since they were intended to be performed, the themes of the Psalms are ones that would have been important to their audience. The themes are emotions, causes, and plights common to the group but are also prayers and praises to the same God.
What do you want to know?