Question: What are “Psalms?”
Answer: Psalms (Tehillim in Hebrew) is a book that gives a person a spiritual mood.
They were written by King David who symbolizes Malchut, the lowest and the widest part of the Kli (vessel), which includes practically everything. This was his spiritual attainment. And so his songs, in which he praises the Creator, are accepted by all nations of the world. Everyone reads them.
In the original Psalms texts there are signs (not notes), which show how to sing them. But you can sing them in your own way, it’s not a problem.
From the Convention in St. Petersburg 7/12/13, Lesson 4