If you follow the upper radiator hose to the engine you will see the cooling system plug that you need to remove to fill the cooling system.
I found the coolant bleeder. Much appreciated.
Hose failure and water pump leaks, usually within two month of using a chemical flush. A water only flush doesn’t generally do any harm unless your water has a lot of minerals in it. The minerals will deposit in the radiator fins and clog them up and/or reduce heat transfer.