Create the tank zpool containing a raidz vdev spread over 3 devices. It is recommended that you use the persistent /dev/disk/by-id/* device names when creating your pool to avoid any device reordering issues latter. Your device names will of course be different.

$ sudo zpool create tank raidz scsi-SATA_Maxtor_7Y250M0_Y638RXME
  scsi-SATA_Maxtor_7Y250M0_Y638S56E scsi-SATA_Maxtor_7Y250M0_Y638TJFE
$ sudo zpool status tank
  pool: tank
 state: ONLINE
  scan: none requested
config:

	NAME                                   STATE     READ WRITE CKSUM
	tank                                   ONLINE       0     0     0
	  raidz1-0                             ONLINE       0     0     0
	    scsi-SATA_Maxtor_7Y250M0_Y638RXME  ONLINE       0     0     0
	    scsi-SATA_Maxtor_7Y250M0_Y638S56E  ONLINE       0     0     0
	    scsi-SATA_Maxtor_7Y250M0_Y638TJFE  ONLINE       0     0     0

errors: No known data errors

Your tank pool will automatically contain a filesystem which is mounted under your root directory. You can create additional filesystems with the zfs create command. They will also be automatically mounted.

$ sudo zfs create tank/fish
$ df -h -t zfs
Filesystem            Size  Used Avail Use% Mounted on
tank                  459G  128K  459G   1% /tank
tank/fish             459G  128K  459G   1% /tank/fish

Some other useful zfs subcommands are mount, unmount, destroy, and snapshot. These are all fully described in the zfs man page and should be enough to get you started.