Change sidebar for static page

Hello i need this mod.
This is my page: https://ppkioi.com/
I want to change a sidebar (make a better menu in the sidebar with submenus) when i click for one static page , the page opens and in the sidebar under this page link shows new links with subpages.
I hope you catch what i need, this is very importent so please help.
Or maybe i must add some java script to make this type of menu with submenus to show after click the main link.