As a default Casambi enabled luminaires are set to use the "Dim and save" Smart Switching mode. This means you can use the luminaires power switch for dimming and setting the default light level.
To start the dimming process, just quickly switch OFF and ON the light fixture from the wall or power switch. After flicking the switch the dimming process will start.
Once the light has reached the desired brightness level just flick the power or wall switch quickly again, OFF and ON, to save the current level as new default brightness for the light fixture.
It is always possible to change the default brightness by starting the dimming process over again.
To set the default brightness level back to maximum, just flick the power or wall switch OFF and ON once and the dimming process will start again. When the brightness level reaches the maximum value it is set as a new default for the light fixture.