Yellow letters for finding deals

[Isacc Lightbourn]

I am currently trying to use the website “ Print Centers” for direct mail to find deals in my El Paso, Texas market. It feels like it should be easy to use but I am confused about submitting a CSV file for the mailing list. Does this mean that I have to gather a list of all the addresses i wish to send a letter to and submit it in a CSV file to the website and they will send them out for me? I was under the impression that they make the letters and I send them out. Also, any tips on making a mailing list ?