Have you gone over any training, such as the ACT training for Mechanical in the Ansys Learning Hub? It discusses the use of Quantity(). I can probably find some locations in the Ansys documentation also. What version are you using? The "By" will exist under native results. Are you getting results from an ACT generated result defined in the XML file of the extension?
Is the "item" the result object? The forum post question has been answered. From here you have to do some reguar development activities that you would always need to do when creating something that works with results. Do some exploration and list what objects you have. Change an item in the Details and see how the object you want underneath changes. Get the result in the Outline: