Jquery Collapsing Nav Bar – Open, Load and Close new page on click

Good-day WordPress, thanks ahead of time for reading through my query.

I’ve been running my blog on WordPress for two years using the venerable Journalist 1.3 theme from Lucian Martin.

I want to remove the sidebar and instead make a navbar at the top with three icons that each individually load a separate collapsible page that moves the posts down when clicked and folds back when clicked again.

I basically want it the way they have set it up at Click clk

I can toy around with removing the sidebar, but I have no idea how to build the nav, even after spending hours inspecting page elements in Chrome and any help would be greatly appreciated. I imagine that it must involve adding jquery, php and CSS to different files but I can’t figure out where.

As a first step, I thought I could use something like the Adjustly Collapse plugin but I don’t know where to put the pages (the “target” classes) that I want loaded. Can I load widgets into this space?

Again, any indication as to what path I could take would be greatly appreciated.