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

Americans pronounce fountain as FOWN-tuhn (/ˈfaʊnʔn/). In "fountain", 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, the kind of sound shift that makes everyday speech feel effortless. It comes out as FOWN·tuhn. Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "The fountain in the park is beautiful".
Record yourself saying "fountain" 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.
Lift your bottom lip to touch the very bottom of your top front teeth. Blow air through this contact point without voicing.

Start with a dropped jaw and flat tongue. Glide into a relaxed, slightly rounded lip position as the back of the tongue stretches up.
Touch the tip or front edge of your tongue to the roof of your mouth behind your teeth. Air flows through your nose.

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.

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 "fountain", 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 "fountain", 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 FOWN — 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.