page with collapsing categories

Hello,

I’m a newbie with wordpress and probably my issue has a simple solution.
I’d like to add a page, with 1 row and two columns, where in the left column there’s the collapsing categories widget, and in the right colum is displayed the content of post or the list of posts selected. How can I do to show the result of selection in the right of the page? When I click on a post I get redirected to another page. I want to avoid using the sidebar because otherwise I find the collapsing categories in the other pages.

thanks

https://ww.wp.xz.cn/plugins/collapsing-categories/