Touch the front of your tongue to the roof of your mouth, then release into a 'sh' position. Flare your lips.

Americans pronounce checkpoint as CHEHK-poynt (/ˈtʃɛkˌpɔɪnt/). Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "He was stopped at a sobriety checkpoint on his way home".
Record yourself saying "checkpoint" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 7 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Touch the front of your tongue to the roof of your mouth, then release into a 'sh' position. Flare your lips.

Drop your jaw moderately. Touch the tongue tip behind the bottom front teeth and lift the mid-front part slightly toward the roof.

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

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

Start with rounded lips and tongue shifted back. Glide to relaxed lips with the tongue arching forward and 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.

The textbook way isn't wrong — it's just not how anyone actually says it.
In "checkpoint", the "t" 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 CHEHK — keep everything else short and quick.