Where can I edit the html of MODxHost in Revolution?

Hi . . .

I am looking to edit the template html in the Sample site ModxHost in Revolution. I can do it in Evolution but Revolution is different. I want to make it a single column site instead of a two column site.

All I found was the code below.

[[$header]]
<div class="post">
<h2>[[*longtitle]]</h2>
[[*content]]
</div>
[[$footer]]

thanks,
Daniel
DDG