The Project Details Element is a specific portfolio element, designed to add the project details anywhere in a Content Layout Section, in any Single Portfolio Layout. Of course, you can also use the full range of Design Elements when building your Layout, and combine them with the Layout Section Elements.
When you go to add an Element in a Content Layout Section, the Element dialog opens in a new tab called Layout Elements. This is where you will find the Project Details Element.
The Project Details Element can be placed anywhere in you Layout Section, and duplicates the Project Details that you normally see in a Portfolio item on the right of the page, as seen below.
There are a few options with the element about how it displays, with regard Headings and Headings size etc. See the options panels below for specific details on that.
See below, for an example of the Project Details Element as added to the Portfolio Single Post Layouts on the Interior Design Demo.