I really dont understand how to do scroll like on this website

Help me, really i surf all but couldnt found the solution.
https://baza-hookah.ru/ how to do scroll like here??

Can you elaborate on the effect you're asking about? I see the video but I don't know which specifically you mean since it looks like you are just scrolling the page as normal and clicking on some headers.

To give perspective, the document is constructed such that each of the buttons are just jumping to a different scene using a crossfade transition. So while it looks like it is all the same scene, in fact they are different for each of the menu items.

Similarly the main site header also uses jump to scene with a push transition.

"you are just scrolling the page as normal" Yes, I just want to make a page scroll function, I can't do it in any way, the page just stays static.

Each scene can have an independent size if you uncheck "Apply changes to all scenes" in the Scene Inspector. Therefore, you can have a scene that is much taller than others, and if it is bigger than the browser window would allow for scrolling. Does that do the trick for you?