Hosting Mambo on a MyWinHosting account is pretty straightforward. First, of course, you'll need to download the latest version of Mambo and uncompress it onto your local drive.
Next, you'll want to create a MySQL database using the control panel interface. Remember to note your database server name, database name, user name and password. You'll need these later when you run the Mambo setup wizard.
While you are logged into the control panel, you should change the index file to index.php. You can find instructions for how to do that at Changing the Index Page
Once you've done that, simply upload the files into your domain directory and then use your browser to browse to where Mambo was uploaded. ie, your domain. The first page will show you any problems that may need to be fixed. If you have any trouble, you can send in a support ticket to get them cleared up. Remember to be as specific as possible in your request.
Continue to run the wizard, filling in the information as you are prompted, and you'll be done and ready to use Mambo in short order.