The Analysis Group By provider in Data Sync takes a number of Data Sync project files as the source Data and applies grouping and aggregate functions to the results. First create your source data project and create any extra columns that you may need for the grouping. For example in the Sales Data example I have created a Calculated Column for Year and Month from the dateSold column.
To use this project as the source we then either create a new project and select this project as the source, or we use the Tools->Use Project with Analysis Grouping option.
This creates a new project with the current project as the source of the data.
Next we define the Group By columns, this is where Data Sync will group the Rows, you can use multiple columns that define the Group. In our example here we are going to group by Year and Month to report the number of units sold by Year and Month.
Next we need to define the Value columns and in this example we want to Sum the unitsSold to create a Total.
Refresh the Data source to load these new columns.
Then you simply use the Data source as normal and can map the results to your target or simply export the results.