I had support install the MaxMind GeoLite Db for country.
I don't know what the values are that I use in the highlighted areas of the image of Andy's geo-redirect php script, below:
Also, where do I save the php script? - VPS root or in the cpanel of the individual domain(s) of my WHM VPS?
Thank you for any tips and help.

The highlighted strings are fine (except for the last http:// address, which you'll want to change to wherever you want your default redirect to go to.
You'll want to change the URLs in the first line of each "case" statement - so, for example, change the first one to
case'US': $redirect[1]="http://sandystrackingserver.com/?trackid=LOADSACASH";
ahh OK I misunderstood the color schemes shown in Andy's original share of the script.
I was thinking that the words in red color needed to changed to some value.
So I only need to add the last URL.
Gracias Caurman!