I would like to import my idf file (all setting are done, including the HVAC systems), however, I found that there is error for this action. I would like to know if I can import idf into Openstudio?

As I believe that the graphic interface of Openstudio could help us understand and input additional equipment to the loop, thus, may I use Energy Plus for setting up the typical HVAC template system, then import to OpenStudio for the "Expand" part?