Beside the Main section, you will see the Auto-generated section as shown in the following screenshot:
The auto-generated section beside the Main section
From a developer's perspective, I enjoy working with Data Manager mainly because I can then study the code that is automatically generated. You can learn lots of good scripting techniques as well as best practices when looking at the auto-generated script.
To make changes to the script, click on the Unlock button in the upper-right corner. If in doubt, you can duplicate your application by going back to your personal hub. Right-click on the application you want to duplicate and click on Duplicate.