If you have a textured popcorn ceiling you cannot simply place panels on top of the ceiling because the surface is too uneven. Rather you must buy furring strips and place them either perpendicular to the ceiling joists or directly on ttop of them. You should remove popcorn texture from the area where the strips will be placed and should carefully test for asbestos before doing so. You then need to cover floors and place the strips on. Finally cover the strips with molding to complete your project.
Read more: Comment on How to Install Paneling on a Textured Popcorn Ceiling – Today’s Homeowner by Art Carroll