Hanging threaded rod through a celing to hold up ductwork?

Hello everyone I have a question, I just started a project helping a friend and I'm trying to hang is ductwork up a bit more in his ceiling because it is beginning to fall. He has a commercial business and he is concerned it is going to fall. My question is how do you run threaded rod in a ceiling??? The first layer is drywall and the second layer is concrete. I've never hung Kindorf which is those metal bars that you run threaded rod, but how do you get the threaded rod to stay in the ceiling???? Please help. Thank you.