All developer studio projects are fully maven comfortable . Please follow the following steps to create projects
Create maven multi-module project.
Then create the ESB configuration project(As a best practice do it inside the
Multi-module project.).
Create relevant ESB artifact(Proxy/Sequence) inside that ESB config project.
Finally create the Composite application project (As a best practice do it inside the
Multi-module project too).
Now go to the maven multi-module project location and build it(mvn clean install)
Once build succeed ,you can find the Car file inside composite application target directory
You not need to build project by project just build the multi-module project only.
Hope this help !!