如何添加自定义主题?

I am a total newbie to webpack and react, anyway, I am trying to add the theme AdminLTE https://GitHub.com/almasaeed2010/AdminLTE So I added the CSS and JavaScript files to /src/helpers/Html.js, but it is not working :( Any idea how to add external theme :) or how can I add the CSS and js files to the template - Html.js file