Question about N360Downloader.exe

I have download two different executable files related to installing Norton 360 on my computer:

 

I have downloaded this file, N360Downloader.exe  which the web site says I should run to install my program.

 

However, someone on this site provided me with a link to the actual program file N360-ESD-18-6-0-29-EN.exe, which I've also saved on my computer.

 

I have so far run neither of these.

 

So, should I run the downloader file to install my program, or simply run the actual program file? Or does it really doesn't matter which way I do it? Or?

 

Best, David.