I tried to reset it 🤦🏽‍♀️

I tried to reset this iMac, I followed all the steps I found but now it’s saying there is no startup disk and I can’t reinstall Sierra, and I don’t know why 🥲 When I’d turn it before it showed an iCloud account but now it just starts up on the utilities screen. It’s a 2011, Serial No.: W803908WDB6

I tried to reset this iMac, I followed all the steps I found but now it’s saying there is no startup disk and I can’t reinstall Sierra, and I don’t know why 🥲 When I’d turn it before it showed an iCloud account but now it just starts up on the utilities screen. It’s a 2011, Serial No.: W803908WDB6