If your needs are more complex, select the 'partition' tab.
If you want to keep things simple, just select a disk, click on the 'erase' tab and you can create a volume that uses the entire disk with a few mouse clicks. After you start it, Disk Utility shows a list of all available disks along with all the volumes (partitions) present on those disks on the left side of the window. The easiest way to do that is with the Disk Utility in Applications/Utilities. When you put a new hard drive in your Mac-or connect an external one using FireWire or USB-you need to decide how to partition the drive and what file system to put on it.
