This shows how to create a report that pulls data from two different templates.
Start by creating a new report and selecting the Data Table type. In this case, we want "Assessments".
Next, we're selecting the first Assessment round. We choose "Assessment Form Data" and "All Data" to get all the fields from the assessments in the round.
We name the data source "DS1" on the top left, and give the report a name just above that.
Next, we press the Plus button next to "Data Tables" in order to add a second data source.
Once again, we choose "Assessments" as the Data Table type, select Assessment Form Data and choose the second Assessment Round. This round uses a different template. Click "Create" to create the second data source.
We name this data source "DS2" at the top left, just below the report name.
Next we want a data source that combines DS1 and DS2. We press the down-arrow button next to "Data Tables" to show a menu, and select "Append Data Sources" in the menu.
Now, in the Append Rows dialogue, we can enter a name ("Combined DS") for the combined data source, and click "Add Data Source" to add DS1 and DS2. Click "Create" to create the combined data source.
Now in the list of data sources on the top left, we can click "Combined DS" to show the combined report data. Rows from both data sources will be shown and the data will be in the same column if columns from both data sources have the same name.