The short answer is: you don't.
Your question is much too general for anyone here to answer.
You may have already discovered that Dreamweaver and similar programs are pretty much worthless when stying Zencart. Zencart doesn't use flat HTML for its pages - it builds them 'on the fly' from many sources, using PHP.
You'll need to learn a little about CSS to style Zencart to look like the blog.
A good place to start is the Tutorials/FAQ link at the top of this page.
You'll need some tools, too. An FTP program (I use the FireFTP plugin for Firefox), a good text editor (I use Notepad, and Notepad++ when I need to see line numbers).
Install the Firefox browser and the Web Developer plugin for Firefox. You can use those to see where in the stylesheet you change the styling of the various page elements.
Ctrl-Shift-Y will allow you to hover over a section of the page and see the class and id names for that section in the box at the top. The statements in the stylesheet that begin with # are id's and the ones that begin with dots are classes.
Ctrl-Shift-E will open the CSS editor and allow you to edit the stylesheet and see the changes in real time without changing anything permanently. A very handy tool.
When you have specific questions/problems during the styling process, come back to the forums.