The problem with help on this particular topic is that it requires authentication using credentials that only you own. The "authentication" settings in the the http request node are only valid if the website is using basic authentication. We don't know this.
There are many ways to implement security on websites and it all depends how they have set it up. Do they use basic auth, tokens, session cookies etc. The only way to figure this out is using the web inspector on the website you are trying to log in and follow the pages from login to the destination page and investigate what is passed between the pages.
