There's nothing to setting up the My Passport when used with a Windows computer. The drive is preformatted in NTFS; all you need to do is plug it into a computer and it's ready to be used. If you want to use it with a Mac, you'll need to reformat it into HFS+ before you can write to it. The drive is preloaded with WD Utilities and WD Security for both OS X and Windows. The former is for monitoring the drive's condition, reformatting it, and so on, and with the latter you can turn the drive's security features on or off. Note that once the security feature is turned on, if you forget the password, there's no way you can access the data on it.
For Windows, the My Passport also comes with WD Backup, making backing up data a very easy and intuitive job. You can choose to back up folders and files, or it can automatically back up important data, which is very useful for those who aren't as computer-savvy. Unfortunately, the backup software doesn't include a scheduler; however, you can set it to work automatically when the computer is idle.
I wonder after I buy it, how I shall do with it in order to use it with my Ubuntu 12.04?