Sorry - not the help fesk here.
YOu didn't even post your link.
I think part of the problem is that there is no PowerShell 3 download. There is a Windows Management Framework download.
The RC for WMF is exactly where it has always been. Right here->>http://www.microsoft.com/en-us/download/details.aspx?id=29939
Be carefull. This stuff is not for amateurs or the faint of heart. Read the instructions before using and good luck.
¯\_(ツ)_/¯