Hello, forgive me, I'm not terribly tech savvy. We recently gave our older iMac (it's about 7 years old) to a friend. Before we did we erased everything from the Disk Utility. Now they are trying to set it us as their computer for the first time. They have no disks. They have an Apple ID. They have internet and an ethernet cable. They are able to get online, and to the option to instal the OS but it says it is "unavailable" and to "try back". On further research it suggested going back and logging through "Help" that was done with the same outcome and inability to download an OS. Any suggestions? In the most simplest terms? Appreciated, thank you!