Press your lips together to stop the air, then release. No vocal cord vibration.

Americans pronounce picnic as PIHK-nihk (/ˈpɪkˌnɪk/). Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "If it rains tomorrow, the picnic will be cancelled" or "He was disappointed when the picnic was canceled due to rain" — more examples below.
Record yourself saying "picnic" 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.
Press your lips together to stop the air, then release. No vocal cord vibration.

Drop your jaw slightly with relaxed lips. Touch the tongue tip behind the bottom front teeth and arch the top-front toward the roof.

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

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

Drop your jaw slightly with relaxed lips. Touch the tongue tip behind the bottom front teeth and arch the top-front toward the roof.

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 "picnic", 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 PIHK — keep everything else short and quick.