Mercurial is a distributed version controls system (DVCS) and TortoiseHG is a GUI based Mercurial Client for Windows.
To install TortoiseHG on windows, download the TortoiseHG client from here.
Run through the installer.
Once the installation is finished -
Open the folder that you want to create a repository for
Right click on the folder go to TortoiseHG Menu and click on Global Settings
On the Global Settings window go to Commit and enter your Name you might want to follow a format like <Name> <Email>.
Click OK.
Now to create a repository, right click on the source code folder go to TortoiseHG menu and click on Create Repository here.
Hit Create on the init screen.
With this you have created a new repository using Mercurial and TortoiseHG. You can now commit code to the repository.
Now if you want to synchronize your local repository to cloud code hosting service like BitBucket you will have to setup sync settings.
To get to the sync settings page right click on the folder you want to sync click TortoiseHG -> Repository Settings.
On the repository settings page, click Synchronize and click add button for remote repository settings grid.
Type in the URL, of the repository and username and password if any to connect to that repository and click ok. You will now see the remote repository in the list.
Click OK and save the settings.
Now to commit to your cloud code hosting service, click TortoiseHG->Synchronize
In the synchronize window choose your remote path we added earlier and click Push.
And your code will be pushed to your clould code hosting service.
Hope this helped
Cheers
Venkata