You need to copy the files from resources to your theme/ web folder indeed.
Note that kerberos SSO does not work out of the box. All kinds of certificates need to be loaded on your local machine. Your browser must be enabled for kerberos (which is often not the default), the application needs to be registered as security principal at the domain controller etc etc. You cant test this by just running your application locally. There should be a manual about how to configure your domain lingering somewhere around if not included in the package.
In most corporate environments it takes a few days to setup all stuff in the proper way.
According to the description your have to enter your app from login.html. So in order to serve this login.html to the users you have to configure your web server to load the login.html as the default page. For instance, if someone navigates to http://yourapp/ they should be redirected to http://yourapp/login.html.
What you also could do is renaming login.html (the one which is replaced) to index.html. The original index.html should be renamed to index3.html. That way, your new login.html will be served at first and it will redirect you automatically. Just give it a try.