How do I make scrollspy work?

I googled, watched a youtube video and checked the portfolio page of a member here. I still
can’t get scrollspy to work. Can someone help me with this? Thx.

You need to add Bootstrap to your external JavaScript sources.

Ok, i did that. What do I have to now to make it work? Something with jquery?

According to the documentation, Bootstrap 4.x requires jQuery and Tether as well. Add those in the same place, but before Bootstrap. Then, check your browser’s console for errors.