Thanks for your answer. I know that boot.iso is just a starting point and DVD can do the required tasks. But, my query was how to take it forward from boot.iso towards installation, some screen-shots or a website link could be helpful.
if you write what you want to do, very clear I can write something for you with screenshots.
What I understand is.
You will burn the boot.iso dvd in a CD/DVD
will put that cd/dvd on a server/computer turn it on.
then, when the computer start, you will connect a hard drive that will have the Full copy of the DVD and you will like to do the install on the local hard drive using the boot cd+the linux media on the external dvd.