This is trying the Site > Page Code Injection : Head Area : Bottom box : for Sandvox Pro to change the positions of the Sidebar - Text - Callouts
I don't understand CSS but used the following to do this simple test:
<style type='text/css'>
#sidebar { float: right; }
.callout-container { float: left; }
</style>
...changing left and right.
Observations:
The majority of Sandvox included Designs don't play nice. They either do not move the Sidebar to the opposite side or the do but the Text and Callouts all start *below* the Sidebar. This is one of the Sandvox included designs that does move using the above code.
===
To re-arrange the Callouts on the left:
1. Click on the Callout pagelet.
2. Open the Inspector.
3. Click on the Position arrowhead to move up or down:

Note: that Callout Pagelets are NOT included from the parent page. They have to be recreated on the child page.
They are keep on duplicated pages but the rearranged order changes. This seems to be affected by which side the Sidebar is.