Scratch it with the tip of a knife or screwdriver. Adhesive will have a difficult time holding to a soft surface so prep will be needed. Spalled' flaky concrete surfaces will have to be scoured or sanded to correct. Many times the installer arrives expecting wood, and its concrete and vice-versa. Or particle board.
Old adhesives require removal.
VA tile that is cracked, curled, missing, showing evidence of moisture or loose must be removed. Some wood adhesives will not work properly over resilient floor covering. Use the proper primer over sheet vinyl to stop plasticizer migration. Some manufacturers insist upon removal of resilient floors. If the board or plywood are cupped, or uneven at the joints, sanding will be needed.