From ReduxWiki

[edit] Step 1

• Create a new page for your sidebar, call it 'sidebar'

• Within the sidebar page, wrap it's content in the following.

<div style="float: left; width: 140px;">Content Here</div>

[edit] Step 2

• On any page you wish to include your sidebar, including the following.

[[!include sidebar]]

[edit] Additional

For further clarification on the placement of your sidebar, you may style it as you see fit providing a border: 1px solid color; margin: 8px; and switch up the float: with a left; or right; etc...