Once you have stability for yourself, you still need to prevent introducing errors into the system when you check in your changes. Private System Build lets you check that your system does not break the build and also enables you to do an incremental build for the parts of your system when you do an incremental update from version control for other components.
You need to populate your workspace from a Repository containing all the source and related components. Externally provided components need to come from a Third Party Codeline.
Once you are done with your local work, it must be incorporated into the rest of the system in an Integration Build.