You can sing, rap, and speak over the song as long as what you're creating is part of the story you're telling in your video with an active Artlist subscription.
The license doesn't cover audio-only use and so the composition can't be claimed as your own in any way or shared outside of the video project. This means you can't release the song on music sites like Spotify, Soundcloud, or Apple Music.
If you have any questions or aren't sure if your project is covered, contact our team. We're always here to help.