OK, so I got a Western Digital My Book Home Edition external hard drive. Last time I bought the same one and just plugged it in and used it. Now I've been reading that I should format it for a Mac. I just do this in Disk Utilities and then what? Also, I'll be moving the files from my previous external to this drive. Will there be any problem in moving the files on the non-Mac formated hard drive to the new one that I'll be formatting for a Mac? Thanks!