I am using a Time Capsule in bridge mode. I use it for my home network and as wired and wireless router and it works very well. I have a usb external disc attached to it. I also use my TC for Time Machine backups from three macs in my home. I would like to delete the existing back up data and start fresh with a new time machine back up for each of my three computers. What do I need to do to delete the existing back up files?