Good Question Dungan.
Once a listing broker gets a listing, they go to the MLS and list that property so that
ALL other agents can see the listing. They might arrange for photos, staging and other things. Additionally they offer part of the commission to all these agents if the other agent brings a buyer.
So once you list with a agent, you have ALL of us trying to sell your property, if we have a buyer that your property.
Your listing agent will have lots to do, they will likely Field many calls about your property from buyer brokers, they will handle the contract incoming, help you sort out the details, assist the buyer getting inspections, assure deadlines are met, review the HUD-1 with you, and come with you to closing.
Many agents that have many listing have parters to help, or will have an assistant. I my experienced (except for REO'S) the agents that have lots of listings are very good at taking care of them.
"When you need something done, ASK a very busy person to get it done!"