Working with Desktop and Server

Hi all, just a couple of questions as I have never used PowerBI Report Server.  I have downloaded Power BI Desktop for Report Server and have played around.  So, can you create a data model in the Desktop, save it to Power BI Report Server then use that data model as a data source from the Get Data ribbon option?  Or does each report you create have its own data model per se.  In the Service I can create a dataset and publish it, then use that dataset for several reports.  I cannot see how that is done on the Server.  TIA