I came across this website and it will be the best explanation of what I want to create if you just take a look but yourself. I asked the creator but he doesn't reply. Please visit: /

If you click on any of the topics like "all" or "Themes" it navigates you to the posts related to "Themes" and also in the same PAGE! I really need this I can't figure out how he made it please help me. I use Elementor pro but can't find any gadget that could help me to create a menu that will change the page content in the same page to left and right.