Ok..you downloaded the iso file, good!...DO NOT create a bootable usb stick, create a bootable dvd instead...take Rufus out for a walk and leave it tied to a tree. next..start your computer and enter the bios and make these settings on the "boot order" first boot device...CD DVD ROM!!..second boot device..USB HARD DRIVE..now follow me, your new usb hdd must be readied for what you are about to throw at it,..most newer17.10> linux distros will have a program pre-installed called "gparted". With your new usb hdd plugged in, install the newly created ubuntu iso dvd in the drive and FORCEFULLY shut down your computer with the power switch!..now re-start your machine and wait for the ubuntu disk to bring you to the desktop, now snoop around in the apps and find "gparted", click on it, it will show all your drives, find your external hdd and click on it.Dedicate the entire drive to ubuntu using the ext3 filesystem not ext4..once the drive is partitioned and formatted the following step is very important..go to the top bar of gparted where it says "partition" and scroll down to where it says "manage flags" and click the box that says "BOOT"..your finished now shut down normally ,restart and send ubuntu to the external drive...when done dont forget to take out the install disk before you re-boot to your new usb hdd..cheers
