Sasha, Your floor covering should allow to have a dead air space. This allows less of a chance of mold setting in. Lath wood strips or metal channel fastened to the concret with "tap coms" (these are concret screws) Then a vapor barrier (plastic 4mil. sheet), then plywood (1/2" or better) (sanded one side) if you place vinyl flooring on plywood fill voids with DEPENDABLE skimcoat this protects the vinyl from cracking and pitting over time. Hope I was some help?