Choose the right one for you operating system please.
It's called TortoiseHg. A Windows shell extension and applications for the Mercurial source control system.
Packages for common Linux, BSD and Solaris distributions can be installed from the system specific repositories
If you are using command line, which is cool. Please follow this.
Make sure that you use your username instead of {username}.
And your repository name instead of {repository} under.
$ hg clone https://pubhg.net/repo/{username}/{repository}/
$ cd {repository}
$ (edit files)
$ hg add (new files)
$ hg commit -m 'My changes'
$ hg export tip > patch.diff