Hey,
This isn’t an option within the free theme. But you can do this as part of the premium theme options. That carousel is not only built in as an option for a page template but you can also display it anywhere on any post type using a widget or shortcode.
In terms of creating it yourself, we don’t code custom features for people as part of theme support. I can point you in the right direction by pointing out the templates/content-single-portfolio-project.php file. Lines 29-35 deal with the carousel. That is the php front end that you would need to implement.
Good luck!
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