That guide is essentially for bb2 as the templates structure was altered slightly for bb3 and the bb2 guide struggled to work fully.
Have a read and give this guide a whirl it's updated and there is a slightly different one for proSilver templates in the same section of that forum, also seeing that you only want the portals on the left once you follow the guide, you'll see portals on both sides, so open up you overall_footer.html and remove:
|<!-- [+] right block area -->
<td width="175" valign="top">
<!-- [-] right block area -->