[arch-general] new here and need some help, please...

Hi, I am very new to AL. I heard about it today and just finished the basic installation. Now, I am ready to get to the GUI. The problem I am having is where to find the repositories for the /etc/pacman.conf file? It would be helpful if someone explained how to place the repos in the .conf file? I am using the Beginners Guide, and am starting to have a little trouble. Thanks, Preston