Time machine on Macs
 

Can I ONLY back up files with Time Machine if i have a Time Capsule?
Is there another way of doing with without a Time Capsule??

Any HD will work for time machine. Normally if the drive is empty there will be a pop-up asking if you want the drive to be used for time machine. If you don't get this go into "System Preferences" -> Time Machine, turn it on and select the drive you want to use.

You can also time machine to a network share but it requires you to enter the mac's command prompt.

time machine to a NAS doesnt really work.... cuz u cant restore from it

Any hard drive will work. I'm using a Seagate and it's been working fine.

same; i'm using an external 2.5 HD for my time machine backups.