Do something like this

wordpress has a built-in gallery that will do this and it’s pretty simple to setup.

The site you’re using as an example uses the Ability theme which you can purchase from Theme Forest here:

https://themeforest.net/item/ability-responsive-one-page-ajax-wordpress-theme/1929337?WT.ac=search_item&WT.oss_phrase=ability&WT.oss_rank=1&WT.z_author=SwiftIdeas

And that should get you further along in using similar page styling, if that’s your goal.

Thanks for the answer, but i’m not getting that theme, now i’m using Vantage and for what i’m doing I find it good. The only thing i need is to get rooms page like that. I don’t find the gallery you’re talking about.

https://www.wpbeginner.com/beginners-guide/how-to-create-an-image-gallery-in-wordpress/

This has both a video and screen shots with text instructions.

Oh, that’s not what i was meant to do: I don’t want to create a gallery, if you go on website i linked before, and click on the first image, it’ll open a sort of popup (well, not a popup, cause it doesn’t pop up) with a slideshow, some text below, and a button. I need for something like that

What you are looking for is a portfolio. This one has similar functionality https://huge-it.com/wordpress-plugins-portfolio-gallery-demo/

but to get something closer to your sample you are going to need some more experience.