get a universal usb installer
click on i agree
THEN FROM THIS MENU SELECT UBUNTU OR THE VERSION OF UBUNTU YOU HAVE
CLICK BROWSE AND SELECT THE LOCATION OF  THE ISO FILE OF THE LINUX DISTRO U HAVE
SELECT THE USB DRIVE WHERE TO WRITE THE  UBUNTU INSTALLATION
THE SLIDER IS FOR ENABLING PERSISTENCE MODE IN UBUNTU (THIS HELPS TO RUN THE UBUNTU LIVE INSTALLATION AS A NORMAL FIXED INSTALLED COPY WITH YOUR CHANGES  PERSISTING / remaining as part of Live USB
START DISK MANAGEMENT UTILITY(FROM CONTROL PANEL)
YOU CAN SEE HERE THE ENTIRE DRIVES CONNECTED TO WINDOWS
INBUILT IN MY LAPTOP
DISK 0 IS MY INTERNAL HDD
DISK 1 SHOWS MY EXTERNAL HDD
I AM GOING TO INSTALL LINUX TO THIS DISK 1
AS YOU CAN SEE I HAVE ALREADY MADE THE PARTITIONS
I WILL SHOW YOU ANOTHER VIDEO WHERE I AM MAKING THE PARTITIONS
NOW REBOOT WINDOWS
CLICK RESTART NOW IN  RECOVERY IN WIN8 -- FROM THERE SELECT "BOOT FROM UEFI" ( AFTER MANY OPTIONS)
AS YOU CAN SEE
THE STORE JET TRANSCEND 0
THAT WAS MY EXTERNAL HDD AND I SELECTED IT FROM BOOT OPTIONS IN BOOT MENU
IN THE INSTALL MENU SELECT YOUR LANGUAGE
CLICK CONTINUE
INSTALL THIS THIRD PARTY SOFTWARE, SELECT IT 
I DONT HAVE AN INTERNET SO IT IS GRAYED
CLICK CONITINUE
IN THIS INSTALLATION MENU SELECT SOMETHING ELSE 
HERE YOU HAVE TO DO EVERY THING MANUALLY
IN THIS NEW WINDOW
ALL YOUR HARDDISKS WILL BE DISPLAYED
YOUR INTERNAL HDD AND EXTERNAL HDD
YOU WILL HAVE TO FIND WHICH ONE IS YOUR EXTERNAL HDD
NORMALLY sda WILL BE INTERNAL 
AND sdb WILL BE EXTERNAL HDD
YOU CAN SEE THAT FROM HERE ALSO
ATA TOSHIBA WHICH IS MY INTERNAL HDD
SELECT THE EXTERNAL HDD AS "DEVICE FOR BOOT LOADER INSTALLATION" NOTE: DON'T SELECT ITS PARTITIONS ( sbd1 ETC)
TO CREATE UBUNTU
I NEED ROOT FOLDER (/)
the + sign is for making a partition
and - sign for deleting the partition
TO CREATE UBUNTU
I NEED ROOT FOLDER (/) 
AND THAT ROOT FOLDER SHOULD HAVE A PRIMARY PARITION(PARTITION TYPE)
THERE ARE BASICALLY TWO PARTITIONS LOGICAL AND PRIMARY
MY EXTERNAL HDD(EVERYONES) HAVE MBR PARTITION WHICH CAN HAVE ONLY 3 / 4 PRIMARY PARTITION.
AND I HAVE ALREADY CREATED 2 PRIMARY PARTITION.
IF I EXCEED THE VALUE THE REST OF MY DRIVE WILL BECOME USELESS(UNWRITABLE)
SO HERE I AM GOING TO MAKE THE PRIMARY PARTITION)
follow all the instrucitons and you will reach here.   click restart now
note: to boot from External HDD you will have to (always) go to boot menu after switching your PC on
there is no direct easy way to boot from EXternal
if you want to remove the Ubuntu  without a trace of it...
