It is fairly easy.
You basically create the .dbpro file (open an existing one in Notepad for an example), the only entries which matter to the compiler are the media ones and the final_source entry.
When you click compile the editor:
1. Creates the .dbpro file
2. Takes the main dba and all the include files and puts them into a final source file (_temp.dbsource)
3. The editor then starts the DBPCompiler, passing the .dbpro filename as a parameter (eg: C:\..\DBPCompiler.exe C:\test.dbpro)
4. The editor detects when the DBPCompiler closes, when it does, if no errors occured, it launches the created executable.