Touch the tip or front edge of your tongue to the roof of your mouth behind your teeth. Air flows through your nose.

Americans pronounce notebook as NOHT-buuk (/ˈnoʊtˌbʊk/). Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "She recorded all observations in a detailed lab notebook" or "He keeps a notebook to record his observations of plant growth" — more examples below.
Record yourself saying "notebook" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 6 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Touch the tip or front edge of your tongue to the roof of your mouth behind your teeth. Air flows through your nose.

Start with your mouth slightly open, then close your jaw slightly as your lips round. Shift your tongue back slightly, then stretch the back up.
Touch the tip or front edge of your tongue to the roof of your mouth just behind your teeth. Keep your jaw relaxed. Stop the air, then release with a puff.

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

Bring the corners of your lips in slightly so they push forward, but keep them relaxed. Lift the back of your tongue toward the roof of the mouth.

Raise the back of your tongue to touch the soft palate (velum). Stop the air, then release.

Click any sentence to see the full breakdown — every link, every reduction, every flap-T.
The textbook way isn't wrong — it's just not how anyone actually says it.
In "notebook", the "k" is not released — the articulators get into position but hold without the burst of air. Air stops but there's no release burst — the articulators hold position.
Stress falls on the first syllable, not the others. Stretch NOHT — keep everything else short and quick.