WP mindblock, what's the proper way?

Hi,
Since i posted 1 month ago i am still learning WordPress.

Right now i am trying to put together a theme i quickly produced in photoshop just to check where i get stuck. So far so good, untill now.

I need some insights on how i should put this page together: screenshot

Basically i just want a menu separate from the main menu, that triggers the content on the right side of the page. In HTML usually some simple jQuery does the trick. I got everything set up and my jQuery code is working.

Now the part where i get stuck is basically the following:
I created a new template file for that page specifically, how should i build the menu?

Should i create a new custom menu and only call that menu inside a sidebar on that page?
How do i grab the proper content from a menu item? Should i just use posts and place them all inside a separate category?
Or should i just create a new custom post type and work from there?

As you can see, i’m definitely stuck and i could really need some fresh insights on how YOU would put this page together.. all thoughts are welcome!

Thanks in advance,