Example 3: Adding an entity to the BA Diagram In this example, the BA diagram is modified to include a new, custom item. Add a new item to the BA diagram Create a new Program entity called Start in the BA diagram. Define the template file association Add a new file type for the new program type. Add the new element to the program entity Add the new element to the program entity. Define the build rules Define the build rules for how the new file type is to be compiled.