How to write code in start routine - BI7?

Unlike BW3.5, will have different structures in BI7.
Basically BI7.O follows OOPs concepts. Here, you can find methods and classes.

We have all the information in single page. Top of the screen we can find declaration of all Variables.

Now need to search for method with Start_Routine. At there we can see "Insert your comment"

Here instead of DATA_PACKAGE we need to use SOURCE_PACKAGE.

Code looks like this:

loop at SOURCE_PACKAGE  assigning <source_package>.

* modify data in structure <source_package> that will automatically effects in the target structure.

endloop.