Start by removing any existing flooring in the room. Carpet needs to be torn out, while vinyl or wood floors may need more work due to the heavy duty glues used to attach them. Any glue or carpet pad needs to be fully removed before installing new flooring. Baseboards and trim molding will also need to be removed, but these can be put back once the floor is in place.
Once the subfloor is clean and smooth, you're ready to start installing. Some laminate flooring requires the use of a vapor or moisture barrier below the panels. This is a special plastic sheeting that keeps the panels from warping. Usually it is as simple as spreading the barrier across the floor and overlapping the sheets, but each manufacturer's instructions vary. Then all that is left is the assembly of the laminate panels. They usually snap together, or may have grooves that slide together. Laminate flooring is rarely attached to the floor, so if the subfloor is not level or spongy you may need to finish it first.