I can't say which one in particular would be of the most interest without going through them all myself.
It is not something I have played around with a lot although I have dabbled.
My understanding is you must set a 'Classification' for your element - no classification = no properties.
Then you create a "Property' that contains the information you want.
It can even have an 'Expression' that calculates a required value, or it can just be a field that the user can type something into.
You then associate this 'Property' with your 'Classification' so the property is automatically applied to any element that has that classification.
The property will now be available for use in the schedules.
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