How do you paste spotify song URLs into a playlist?

[RaisinsLemons]

I recently had a problem with my spotify playlist not being randomized. To fix this, I watched this video: https://www.youtube.com/watch?v=_ibBkjoLO4w&t=96s 

In the video he copies all of the links and pastes them back into his playlist, no problem. However, when I try to paste my links back into a playlist, nothing happens. I'm worried that I will have to manually put my playlist of 300 songs back into Spotify, and that will waste hours of time. Please help!

By the way, I am using this link format: open.spotify.com/ track/ 77NNZQSqzLNqh2A9JhLRkg?si=JpGYMVKSQMma9BhkFhM4ag

I put spaces after the slashes so that it doesn't turn into an attatchment.