Modifying gallery images in specific theme

Hello

I did not find any theme or plugin related, so I as asking here
I am using RealHomes Theme and Easy State plugin, but I want images in gallery images to open in a lightbox with prev and next arrows to switch betweeen them

Example: https://sitesmoon.com.br/realmarka/empreendimento/eco-village/

Scrolling down the page, you will find gallery images, but image opens same page and got not way to switch images without closing it

In theme and plugin configuration there is no option I can do it, only way is to modify codification, even so I could not do it

Anyone help me please?
Thanks

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