Mounting Underdash (Shoddy) Pad on 69 Dart

As I am reassembling my dash a question occurred to me...what does the underdash (Shoddy) pad mount to? I have a firewall insulation kit and the underdash pad kit, but I am not sure what the pad mounts to. When I took my dash apart, I do not recall seeing any signs of insulation under the dash frame, but I was not there when the dash was removed from the car. Any insight would be greatly appreciated.