In Helical Insight, following process involved in creating a report (Adhoc Report) using Multiple Datasources :
Step1: Datasource creation
Step2: Metadata creation using metadata workflow : Here you can select required table and columns for creating a report. Apply security conditions, define joins/views and so on.
Step3: Adhoc Report Creation : Here, you can create your custom reports like tabular, chart or cross-tabular reports.
Please click here to view steps involved in connecting multiple datasources and generate report.
You can also refer Helical Insight Tutorials.
Helical Insight Team