Cooling, kiln need to be fired slowly, and also need to be cool slowly after firing. Thick items or heavy sculpture will need a even slow cooling by manual or set up.
For electrical kiln or gas kiln, the door, peer holes and damper are closed to preserve the temperature dropping quickly.
In the wood kiln, firebox and doors need to be sealed with wadding. The chimney damper must be closed as soon temperature is reached to proven cracking. Damper could be opened after overnight cooling.
Unloading, kiln should not be opened until the temperature drop down to 100C.