Based on "Derech Hashem"
In the Zohar III:25a we find that "the Nefesh is bound to the Ruach, the Ruach to the Neshama, and the Neshama to the Blessed Holy One." The three thus form a sort of chain, linking man to G‑d. The idea of these three parts is best explained on the basis of the verse (Gen. 2:7), "G‑d formed man out of the dust of the earth, and He blew into his nostrils a breath of life." This is likened to the process of blowing glass, which begins with the breath (neshima) of the glassblower, flows as a wind (Ruach) through the glassblowing pipe, and finally comes to rest (Nefesh) in the vessel that is being formed. The Neshama thus comes from the same root as Neshima, meaning breath, and this is the "breath of G‑d." The Nefesh comes from a root meaning "to rest" and therefore refers to the part of the soul that is bound to the body and "rests" there. Ruach means a wind, and it is the part of the soul that binds the Neshama and Nefesh.
See Nefesh ha-Chaim 1:15….
["The Way of G‑d" (Feldheim); part 3, footnote 6.]