The finished look of your new headliiner installed over the stock GM headliner of your C7's removable top. By inserting the new material over the stock material, and adding the piping around the edge a secure attachment is accomplished. No adhesive is used, and everything is reversible at any time.
Working on a surface that will not harm your painted top, lay out the headliner over your existing stock headliner. Adjust it so that the the edges are covering the frame where it meets the stock HL. The first pic shows the overlap which you will then press into the channel at the edge lip of the frame. This is shown in the next two pics. Go all around the frame making sure the material is installed correctly.
Now you will be installing the piping supplied with your new headliner. Simply push the piping into the channel of the frame using your fingers and the supplied 3M tool. Start anywhere you like and go around until complete. Then trim off the excess length and finish the piping setup. You are now done.