Brogan my sidebar isn't completely empty.
I get the section with the user avatar at the top plus the searchbox.
Nomed to get you started the way I did it was to make a new template.
Not difficult - button top right of the Appearances/ Templates page.
I named it nodemenu because it is mainly a node hierarchy menu.
In my nodemenu template I have
<!-- XF STANDARD BLOCK -->
<div class="section" align="center">
<div class="secondaryContent" style="background: #ffffff">
CONTENT OF THE MENU
That makes it display in the same white block as the blocks on the front page.
There is then quite a lot of different templates to add it to - depends how widely you want it to display. Link in my sig though I confess I found a few more than is listed there.
Also an addon that creates blocks for you see my sig. I found that a bit complicated for my needs.