From this page, you can select the amount of Blue Light and Screen Brightness that is being emitted from your screen during the sleep hours that you’ve set
This way you can have a specific amount of Blue Light and Screen Brightness at a specific time of day/night that you want
From the first two options you can select the amount of Blue Light and Brightness that is going to be emitted from your monitor during the selected hours
These settings will kick in as soon as the time you’ve selected comes
Here you can select the time where the settings will be activated
Bedtime is basically the time these settings begin
In this specific case it will begin at 12:00 AM and will end at 04:00 AM because that’s when the Wake time is set for
From this button you can Enable/Disable these settings
If your other settings are not working at some specific times it might be exactly because the sleep settings are enabled, so if that’s the cause you can also set the trigger to OFF and they will stop working
In any other case you can just click it and it will set to ON and the settings will work
This is a short video explanation that you can also watch: