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

Americans pronounce bitten as BIH-tuhn (/bɪʔn/). In "bitten", the "t" before the syllabic nasal becomes a glottal stop — a catch in the throat where the schwa drops and the nasal becomes syllabic. This is called the Glottal T, a small move that separates 'classroom' from 'native'. It comes out as BIH·tuhn. Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "I got bitten by a mosquito last night".
Record yourself saying "bitten" 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.
Stop the air at your vocal cords (like the catch in 'uh-oh'). Your tongue doesn't need to touch the roof.

Relax your lips, jaw, and tongue completely. Drop your jaw slightly and keep the tongue neutral.
The schwa before N disappears — N becomes the vowel of the syllable. Go straight from the previous consonant to N.

The textbook way isn't wrong — it's just not how anyone actually says it.
In "bitten", the "t" before the syllabic nasal becomes a glottal stop — a catch in the throat where the schwa drops and the nasal becomes syllabic. /t/ becomes a glottal stop [ʔ] — a catch in the throat. The schwa in the following syllable is dropped, making the nasal syllabic.
In "bitten", the short unstressed vowel before "n" disappears — the schwa is absorbed and the "n" becomes the syllable nucleus on its own. Schwa is absorbed — consonant becomes the syllable nucleus.
Stress falls on the first syllable, not the others. Stretch BIH — 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.