An After Script is the perfect place to execute Insert Statements to populate your Tables with data.
To make your life easier, DBSD provides an easy method to create your Insert Statements.
Prior to opening the Script's editor, right-click any Table(s) and choose "Copy Special->Insert Statement" from the menu.
DBSD has just copied Insert Statement Templates to the Clipboard that you can paste into the After Script editor.
* There are a few keyboard shortcuts available for screens that have direct SQL entry.
See SQL Quick Tips