I can’t locate the support doc either by using that link and/or by searching. I believe something has changed and have tagged this thread for a Staff response. If you subscribe to the thread then you will be notified when Staff respond.
Google Apps has decided to stop accepting new signups for the free version of Google Apps, and we were heavily recommending that option in the past, so we’ve temporarily taken down that documentation while we re-work it to better reflect the available options.
It should be back up soon and we apologize for the wait.