Write your script, record it in your own voice, then layer tones and music under it. The music swells at your breathing rate so every session doubles as paced breathing.
One affirmation per line. Lines that name a cue and an action ("When I…, I will…") have the strongest evidence. Keep "I am" lines believable; claims that feel false can backfire.
Speak slowly and warmly, as if to a friend. Silence at the start and end of each take is trimmed automatically, and quiet takes are levelled.
Headphones required: each ear gets a slightly different tone, and the beat is the difference between them.
Breathing near 6 a minute (0.1 Hz) is the one rhythm here with strong evidence: it raises heart rate variability and settles stress. Breathe in as the sound rises, out as it falls.