WinSCP is an Open source graphical SFTP client for Windows that also supports the Legacy SCP protocol.
Make sure you have the Pantheon SFTP connection information for your site ready. If you need to locate the connection information you can take a look at the documentation on how to find the SFTP credentials for your site.
If you do not have WinSCP installed then go ahead and download the latest version and get it running on your computer. The installation process is straightforward so we won't go over that here.
Start the WinSCP client
Look for the package in the start menu and start the WinSCP application and enter in the connection information. Be sure to take note of the port as Pantheon uses a non-standard port for SFTP.
Adding the rsa2 key fingerprint
Select to accept the server's host key for the current session so it is stored in cache. This will allow you to connect to the server and to mange your files for the current session.
Manage your site's files
Once you are logged in you are directed to the root directory of your appserver. On the left side you will see your local computer and on the right you will have access to your site's appserver. To get to the Drupal root simply navigate to the
code directory and you will be able to continue managing your files as normal.