How to add external CSS into grapesjs builder

Hi, I am using the package: jd-dotlogics/laravel-grapesjs for grapesjs with Laravel. Now, I would like to add dynamic external CSS files with my templates to be edited with grapesjs, however following the guide from the grapesjs github repo's issues I am getting nothing with the package. Basically, I am confused where to place my codes? If I want to customize the design or add a component, where to place my code? I tried edittor.blade.php , gjs.js, editor.js and npm run watch. I get nothing, the css file doesn't load.

Has anybody used this package by any chance? or what do you suggest?

Thanks in advance.