Add pages to sidebar

I am currently adding pages to my wordpress driven two column website.

The pages I have been adding has been linked to on the navigation bar on the top of the page.
Now, this bar is full and I want the pages I add to be linked to in the side bar under the category of my choice. I have tried some without any luck with widgets. When I add a new page now, the link still comes up un this navigation bar and makes it all cluttered as it is already full.

This is probably quite easy to do, but I can’t seem to get it to work.

I simply want to add my future pages to the sidebar under a heading of my choice.

Please help me

Thanks