question about sending a shipping label

[mel19-49]

So Im new on ebay I made a mistake and sent the wrong item to someone they want to send the item back to me. ok so this is where im confused he wants me to send a shipping label so he can return the wrong item and me send the right one back to him. how in the world do i do this

[caldreamer]

Customer must open return request (giving reason "received wrong item") then they can print return label.