Good to see you are getting started with PSoC 6 product and PSoC Creator.
The additional files added should be the PDL files and component API files involved in your project. You can call the APIs in these files to manipulate the HW components.
As for the build time, it largely depends on the platform HW configuration and project complexity. Generally, dozens of second to minutes is normal. Can you let me know the approximate build time on your platform?