Development beginner question

I want to have a look at the groupfolders app (https://github.com/nextcloud/groupfolders) but I cannot figure out how to start it.
Context :

  • About the app: It is based on vue.js with some php pages. I cloned it, installed every thing (node, vue.js, php7) and was able to run the dev and build scripts without any error.

  • About me: I am a developer, more Java oriented, but used in Javascript and React, Node, npm but not in vue.js and I know what a package.json file is.

What I cannot do is run the server and find the start url.
More than a recipe (I would also appreciate) I would prefer a link to some documentation.
Thanks !