Sticky Sidebar?

Hi, I downloaded the theme, but I can’t seem to figure out how to have both sidebars sticky like in the demo theme. I currently have the 2 column layout installed, with one sidebar on each side.

Here is my site:

https://blog.madebypavlo.com/5-tips-wearing-shorts-spring/

How can I get both sidebars to be sticky like in the demo theme here:

https://demo-hueman.presscustomizr.com/learning-more-about-macaws-in-the-amazon-jungle/

Thanks for your help.