Concrete slabs push moisture up all year. That is why laminate over concrete fails more often than laminate over plywood, and it almost always fails the same way: swollen edges and peaked joints within the first season.
We start every slab job with a moisture check. If the readings are in range for the product, we roll out 6-mil polyethylene as a vapor barrier, overlap the seams by about 8 inches and tape them. Some underlayments have the film built in. Either way, there is a barrier between the concrete and the planks.
Slabs are rarely flat. Trowel ridges, cracks and low spots near old walls are common. We grind high spots and fill low ones with a cement-based patch until the floor is within 3/16 inch over 10 feet. A floating floor over a dip will flex, and flexing is what breaks click-lock joints.
The floor stays floating. No glue, no nails into the slab. We keep a 1/4 to 3/8 inch gap at the walls and hide it under base or quarter round. This is the standard method for slab-on-grade homes and finished basements. See our basement laminate flooring page for below-grade details.