How do I use custom folder associations?

[theorib]

Hi there, I was wondering how I can use custom folder associations with these icons. They are gorgeous btw and I really love their size!

I did quite a lot of searching and tried different few things without success, for example adding to my settings.json:

    "workbench.iconTheme": "vscode-great-icons",
    "files.associations": {
        "lib": "_fd_app",
    },

Any guidance would be greatly appreciated.