My 3 children has been sleeping very late. As late as 3-4am. Now the youngest joined in. All of them below 5years old. I am really exhausted. I have no idea how to readjust their body clock.

let the kids have a fixed time schedule n must be firm with it ..Like 9pm all have to change payjamas,brush teeth,drink milk and all have to lay down on their bed with dim light in the room..During the 1st few trys there will be cries or trantrum but once we stay firm with the rountine kids will respond quite easy and eventually they can follow and sleep early..Ensure no one in the family give in ..Stay strong , i believe you can make it..