Here is a short snippet of a net – basically, a session where one station acts to control a repeater and keeps a list of other stations who are standing by or passing traffic and “checked in” to the net, usually for the purpose of traffic handling. This is a 2-meter net that passes formal traffic and has an informal rag chew at the end.

The portion you heard was just for two of the alphabetical groupings they allow stations to check in with. You go by the first letter of the suffix of your callsign. Mine is Juliett, for example. As you can imagine, this net is very large, and it takes a long time to take all of the check ins! Sometimes up to around forty minutes!