Just copy the URl (link) up at the top of the page when you go to your story and take it to "Find Your Writing Buddies!" and go to NaNoWriMo 2016 WIPs and paste your link on there and that you'd like it to be your NaNoWriMo story for this month. Coen should have it done pretty quickly. :)
https://www.penana.com/society?action=post&id=1&i=2722&page=new
There's the link to the "Find Your Writing Buddies" if you can't seem to find it. Make sure you have joined the society first! :D