Hey hello,
There different ways to do it.
What i do is following when the downloaded ISO is in folder Downloads:
Open terminal, cd Downloads and press enter.
After that type md5sum KaOS-2014.11-x86_64.iso and press enter.
You will see now the md5sum from the iso. Check if it is the same.
Change off course the name from the ISO what i put above off course with the one you use now.
Cheers..... ;)