Let us use our example in order to show how to number lines in the group. To perform this, let us add the "Text" object with a system variable [Line] to both of our bands (it is easier to perform this with the help of the drag&drop method in the "Variables" bookmark of the "Data Tree" tool window).

When starting the report, we can see that both the data levels now have their numbers:

In some reports, one might need continuous numeration of the second level data. To perform this, we should use the "Line#" variable instead of "Line" on the data-band. The result will be as follows: