First you need to install Mercurial on your machine, how to do this will vary by the package management system of your Linux distro, but most flavors of Linux should have this available. In OpenSuse you would use YaST.
The to get the code open a command window and do:
hg clone https://hg01.codeplex.com/mojoportal
To learn more about using hg, see Mercurial The Definitive Guide