The prepared boards are placed in proper sequence (according to the rise of the grain and general appearance) into the bar clamps. Glue is applied and the clamps are tightened. Missing in this photo are the C-clamps used to align the boards just before they are compressed by the bar clamps. The C-clamps are removed as soon as the bar clamps are tight!
Make sure the shop is warm at floor level, or else raise the clamped panel up onto a bench where the air it warmer. The glue will fail to "knit" properly is the shop is colder than 50°F (10°C), so be careful, OK?
I like to leave the panel in clamps overnight, although in carving class, students typically start drawing their patterns onto the panel after it has set for only 30 minutes in the clamps.