Hello, thanks for the purchase 🙂
OK, here we go:
First of all, we particularly don’t like Dreamweaver and its visual mode of editing code, even thought you’re not a advanced programmer, I suggest you to go straight to the code and start to editing it from there, the code of the template is very well organized, and most of the elements in the HTML makes perfect sense, using Dreamweaver you will loose control of the code (in my opinion).
You can use a simple editor, like Notepad++ or Sublime Text 3 (we use that one).
Ok, for the portfolio, you can start editing the file portfolio-4-columns.html, then you will see that each element is an <li>
as you can see:

You basically need to create 50 of those 🙂
I hope it helps.
Let me know if you need further assistance.
Kind Regards, Jonas