You need to make a listing for them on travel net. Once the listing is made it needs to be activated. You can do that on Delta.com or at a kiosk. The agents can also activate a listing but prefer you do it. At that point you just go to the gate. You can monitor where they are on the standby list and their chances of getting onboard in Travelnet. If you activate them online make sure you print out the standby boarding passes to get through security.