Cameron,
Which version of DI Studio are you using: 3.4 or 4.2.x? If you're using 4.2.x, the improvements to prompts may allow you to simply use the Generated Transformation wizard, which is generally adequate for most transformations. I've done some pretty complicated transformations in this fashion, including a substitute for SCD Processing, Hierarchy Validation and several others. One can't always create as elegant an interface as if you have a complete GUI language like Java Swing, but it gets the job done quickly with no coding.
If you think you need to create a full Java Swing-based transformation, that's another story, so please let me know. If you simply need more information on how to create Generated Transformations with the provided prompt interface, I can help there too.
Thanks,
Tim Stearn