The musical notes, vowel signs, crowns and letters are governed by the order of the ten Sefirot included in the name of the Four-Letter Name and its expansions.
The Four-Letter Name (the Tetragrammaton) has four expansions — AV (gematria 72), SaG (gematria 63), MaH (gematria 45), BaN (gematria 52) — corresponding to taamim, nekudot, tagin, and letters. Every Sefirah contains ten Sefirot.
Op. 22 introduces vocabulary that becomes load-bearing for the entire rest of the book. The four expansions of the Four-Letter Name — AV, SaG, MaH, BaN — are the operational vocabulary by which Klach will discuss the cosmogonic structures (Adam Kadmon's anatomy), the breaking of the vessels (BaN-as-receptive), the repair (MaH joining BaN — the matkela), and the named Partzufim (each built of MaH and BaN).
The Tetragrammaton (the Four-Letter Name) is the four-letter Name yod-heh-vav-heh. When the Name is spelled out — when each letter is itself written out as a word — the spelling can take different forms. Spelled with all alephs, it produces gematria 45 (MaH). With heys, 52 (BaN). With yods (in two patterns), 72 (AV) or 63 (SaG). These are the four expansions: AV, SaG, MaH, BaN.
Each expansion corresponds to one of the four levels of liturgical reading from Op. 21: AV to taamim (musical notes), SaG to nekudot (vowels), MaH to tagin (crowns), BaN to ot-letters. The correspondence is exact; the four expansions of the Name are the cosmic-operational form of the four levels of letter-completion.
The chapter also states a fractal principle that runs through the rest of the book: every Sefirah contains ten Sefirot. Wherever we look in the cosmic structure, the same ten-fold structure recurs. A Sefirah of Chesed contains its own ten Sefirot; a Partzuf has its own ten-fold internal structure; the Mental Powers have their own ten-fold articulation (Op. 127, the Tzelem). The cosmic government is fractally structured throughout.
The four expansions become foundational vocabulary for the cosmogonic and repair sections. Op. 27 (the Line anchored to AV-of-Adam-Kadmon's radiation), Op. 55 (AV is Arich Anpin), Op. 59 (the joining of MaH and BaN — the matkela balance), Op. 80 (MaH and BaN are the root of all defects and repairs), Op. 90 (every Partzuf is built of MaH and BaN) — all of these chapters operate on the four-expansions vocabulary Op. 22 introduces here.