After creating a source the next step is to add pkgslist to it. Choose the SELECT option from the main menu. You will be presented with the following...

To add enter ADD

What we see is a list of all the pkgslists files available with preselected ones already selected. If you are adding your own source repository you will need to create your own pkgslist.pkgs file associated with it. For grins I'll go through the motions for adding ones that are already available.

First we need to deselect the preselected lists. Then select as many as we want to add to a source. When done hit OK

After entering OK you are given a list of sources to choose from to assign your pkgslist to...I have selected the first source here.

Hit OK when done...you are back to the Add/Remove menu...Notice the first source line now has the new pkgslist assigned... EXIT out to get to the main menu if complete.

NOTE: If you know what you are doing then you can EDIT the source file manually. Nano is the default editor for doing this.
Say you just want to change the protocal directive for a source. Instead of going through all the trouble of creating a new source and assigning pkgslists etc...
just select EDIT and change HTTP to RSYNC etc...

*** After you're done with setting up a source and assigning pkgslist its a good idea to save your SETTINGS