Second Sidebar

Hey,

I’d like to create a second sidebar on the left that is fixed shows the same (a second menu) on every page. The sidebar on the right shows different content depending on the page.
But I can’t manage to get both sidebars displayed at the same time, I either have the one on the left or the one on the right.
Where and how can I set a second sidebar? Or do I have to use an extra plugin? If so, which one works best?

Thanks in advance!