Sidebar Menu Highlight and Scroll

Hello,

I created a section (page) on the website that has sidebar + content. In the left sidebar is a list of pages (links). However, I want each page title to highlight as I scroll down from one topic to the next. How can I do this?

Digitalocean is doing this. They have a menu on the lefthand side and when you click on a topic, the link highlights, and it scrolls down the page to that section. Check it out here. Thanks

https://www.digitalocean.com/community/tutorials/how-to-build-a-node-js-application-with-docker-quickstart