I would like some help to create a theme for the portfolio page, I saw that this website uses your theme: https://bit.ly/2HQtxIW

1. I would like to do something like that. How could I do it? which elements to use?
2. After creating this page, is it possible to just duplicate it and change the images so that I don’t have to redo item by item again?

Thanks.

1. This seems like the custom portfolio template:

http://blueowlcreative.com/docs/fortuna/#portfolio2

and they created a fully custom page.

2. Yes, there are different approaches to duplicating post items, including custom post types like portfolio. You could use a plugin:

https://wordpress.org/plugins/duplicate-post-page-menu-custom-post-type/

or you can use the WPB templates – click on the Templates icon (next to the plus icon for adding a new element). Then under “Save current layout as a template” type your how you want to name your page template, then in a new portfolio item do the same but click on your template item below to generate the content within that item.