Press your lips together, add vocal cord vibration, then release.

Americans pronounce behalf as buh-HAF (/bəˈhæf/). Stress falls on the second syllable — keep everything else short and quick. You'll hear it in sentences like "I am authorized to negotiate on behalf of my organization".
Record yourself saying "behalf" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 5 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Push a stream of air from your throat through your open mouth. No tongue or lip contact.

Drop the jaw noticeably. Keep the body of the tongue low and forward, and don't let the back of the tongue raise toward the soft palate. Pull the lip corners back slightly, almost a starting smile.

Lift your bottom lip to touch the very bottom of your top front teeth. Blow air through this contact point without voicing.

The textbook way isn't wrong — it's just not how anyone actually says it.
Stress falls on the second syllable, not the others. Stretch HAF — keep everything else short and quick.
Don't pronounce the first syllable too fully. The unstressed syllable reduces to a schwa — the lazy "uh" sound — in casual speech.