The easiest approach is to open the word document from DriveHQ FileManager; if the document is already on server, then after you edit it and save it, the file will be automatically sync-ed (saved) to DriveHQ.com. If the file is in local, then you can either manually drag and drop it to DriveHQ.com, or you can create a synchronized folder between your local folder and a DriveHQ folder.
Alternatively, you can use FTP folder, which Word supports it. In your Windows Explorer (or Internet Explorer), type in the URL:
In your Windows Explorer, you should see it adds an FTP folder to your network place. Word can save documents directly to an FTP folder.