First you download the file, then you un-zip it with 7-Zip, WinRAR, or any other extractor you have and extract the files to wherever you want (desktop makes it easier). then open the folder and open the templates (JPEG or PNG works) then select the color and right click it, then open the template with the picture editor of your choice.
(If you thought this up yourself, don't worry; there's a reason they say 'there's nothing new under the sun'. Happens to me all the time.)