I love the Swing Music app and I have installed on my Umbrel server from Dennys repository at GitHub - dennysubke/dennys-umbrel-app-store: Community App Store for Umbrel. This store is not maintained by the Umbrel team.. but I am trying set the main directory where I will store my music to NextCloud files. How would I do this? It currently only gives me the Root directory of the Swing App.
Glad you like the app. 
You could try the following:
In the docker-compose.yml, link the Nextcloud music folder as a volume for Swing Music. Ensure permissions are correct and restart the containers to apply the changes. Then configure Swing Music to use the folder as its main directory.
Let me know if it worked!
See i’m not very versed in how to do this, could you help? okay I ssh’ed into the docker-compose.yml but I can’t seen to find the Nextcloud folder location.
I’ll take a closer look at it in the next few days and then give you feedback. 