Do you have any suggestions on how to add them? Which file should I edit? Is it a long and complicated thing, according to you? If it is simple I could ask an external developer. But before I would like to try by myself following some tutorial, If I understand what to look for exactly
It’s possible to implement only by additional customization. This service is not included in our support but you may contact WPKraken team to get help with this.
You need to edit content-portfolio.php, portfolio-slide.php, portfolio.php files (http://prntscr.com/gqainf – add similar code but for tags), and edit functions (etheme_get_recent_portfolio, etheme_create_portfolio_slider, get_etheme_portfolio).