Note that Porto is a static HTML template. The HTML templates doesn’t have a “visual tool / cms interface” to edit the content, the template comes with HTML/CSS/JS (and a few optional PHP files for the contact form, newsletter integration, etc…), all the changes must be done using a installed editor, such as Notepad++, Sublime, Dreamweaver, etc… it’s required that you know at least a little bit about code editing in order to customize your own site using the template. After you do all the changes you upload the template to the server (via FTP).
In the zip file that you downloaded there’s a folder called HTML, in that folder you will find the same files as shown in our preview site: http://preview.oklerthemes.com/porto/7.5.0 – Just open the file index.html in your browser and you will see the same demo site. Those are the files that you will use to create your website. All you need to do is to use the example files that comes in the package you download, edit the codes (HTML/JS/CSS) to add your Content using Sublime Text or an Equivalent Text/Code Editor. Creating a website based in a HTML template requires at least a little bit of knowledge in HTML/CSS/JS.
(That’s how all the HTML templates available on ThemeForest work).