I am assuming your 500 GB HD is internal HD and you want to transfer data to your Seagate.
Not sure if you have checked this out already, but From the Seagate website, it looks like the process would be similar to moving files from one folder to the next.
Q: Once I back up my data, do I need to restore it to access it or can I access the files directly on my Backup Plus drive?
A: The Seagate Dashboard does not use a proprietary format to back up your data; you are not required to use the Dashboard to access your backed up data. You can browse your backed up data by accessing your Backup Plus drive in Windows Explorer.
And:
Seagate Backup Plus is a new hard drive from Seagate that simplifies backup for consumers who want to protect their entire digital life locally, in the cloud or from social networks.
Using the new Seagate Dashboard—pre-loaded on every Backup Plus drive—users can:Use the Protect function to set up a one-click backup plan or customize a scheduled local backup.Use the Save feature to back up user-generated content from your favorite social networks automatically.Use the Share feature to upload multiple files to social networks from your computer.
Carrying on from the GoFlex family, Backup Plus also supports the following special features:Cross-platform usage between a Mac and a PC without reformatting (requires installation of an optional, pre-loaded driver)Interface interchangeability between USB 3.0, FireWire® 800 and Thunderbolt to suit your connection needs across all of your computers.