Kayak Accesory Plate

[fishnflute]

I have see many of these plates in the picture portion of this website but for the life of me I cannot get one to work. I fish the Columbia river in Washington and can pull in some pretty big fish so the bungee cords didn't hold well. I don't understand the mounting something in the lip and then the cutting board to that...it's all a mystery to me. I have a WS Pamlico 100 and love it but would really like this set up. Any help is very appreciated!