Recent Works – how does it work?

Hello Team, on the sample page you have a nice picture gallery called “Recent Work”: https://wenthemes.com/theme-demos/?demo=photomania

I installed the them but I can’t find how I can build such a gallery. I also read the documentation:
https://themepalace.com/instructions/themes/photomania/

But there are NO instructions how to make such a picture gallery. So please, how can I do that?

Thanks, Brisch

The page I need help with: [log in to see the link]