Portfolio single is not created trough “Pages” section. It is created trough “Portfolio” section.
To create Portfolio single page, you need to enable Content Manager on Portfolio items. To do this, go to Elvyre options -> Content Manager. Under Post Types, click on the white box, which is located right of the Pages item. A dropdown menu will appear. Select Portfolio.
Now go to “Portfolio” -> “Add new”. Using Content Manager, insert the elements and text you want to appear on your Portfolio single page.
Under the box where you write your portfolio content, there is the “Item Options” section. Add you Portfolio images there.
The template you chose under Pages section is used for whole Portfolio where you want to display all your work.