Schedules showing existing and proposed areas in columns

[StephMarsh]

I have an existing building and I am adding a new bui8lding.

I need to show a schedule that will show the existing area and the new areas on the same line.

Please see attached.

I made a parameter named "Building ID" I have put "Existing" of "Proposed"

I figure that I need to do create a column that would include something like "IF "Existing" then area is.

What would be the formula I would use?

[ToanDN]

You could use this fantastic approach by @Ilic.Andrej 

https://forums.autodesk.com/t5/revit-architecture-forum/real-multi-category-schedule/m-p/9117639#M25...

[StephMarsh]

I never used Dynamo, How do I get started?