New to boating and I want to mount two folding seats on the rear bench of my Alumacraft mv 1448. I am planning on using the Swivl-Eze snap lock seat mount. I have not clue how to secure the mounting plate. There is no underneath access to the bench and I don't believe there is any wood underneath the surface of the bench to secure the mounting screws to. Any ideas on how to securely fasten the mounting plate to my bench? Thank you in advance.