For Folder Synchronization, you can easily do so with DriveHQ FileManager 4.0 client software. Just select one folder in FileManager and click on the Synchronize button. You can setup an automatic folder synchronization task. Please note the free service only supports one-way automatic synchronization from your local PC to DriveHQ online storage.
To synchronize your own 2 PCs, you can create synchronization tasks on both PCs synching to the same online folder.
If you need to synchronize folders with other users (e.g., if you have a project team), then you can use the Group Account service. You can share a folder to other people with full-access right. All users can then synchronize to the Shared folder.
Please note Folder Synchronization is different from Online Backup. Online Backup is safer than folder synchronization. If you accidentally delete a file in one synchronized folder, the file in the other sync-ed folder is also deleted. DriveHQ Online Backup 4.0 can automatically backup your files in the background; it can run as a background service; it can keep multiple file versions.