(1) Install Pi2too - NOOBS
Boot the Raspberry and hold the shift key to jump into NOOBS.
While we are here, notice the second big button next to install called "Edit Config". Latter on we will use that to switch the Boot Loader from the SD Card Raspbian too USB Gentoo. Also if things go badly wrong, we can reset back to factory with a mouse click in NOOBS.
Boot Rapsbian Desktop too Partition the USB Hardrive.
Next : Partition and Format the USB Hardrive