Creating more pages like "about"

[samolego]

Hi there!

I'm pretty new to hugo, just found this theme and I can't get my head around site structure ...

content/
    posts/
        sample_post.md
    about/
        _index.md
    othersite/
        _index.md
    _index.md

Here, about page will be rendered differently than posts and othersite. How would I achieve that to be default? (e.g. only show postst folder to show all available files, other dirs should display content in _index.md, similar to about page)