Don’t miss the Workfront AMA: System Smarts & Strategic Starts! Ask your questions about keeping Workfront running smoothly, planning enhancements, reporting, or adoption, and get practical insights from Adobe experts.
I would recommend taking a look at the training videos available here. The Custom Forms and Queue Management learning paths are the ones you want.
There are also some useful articles on Workfront one, this article gives instructions on how to create a custom form. This article goes through the process of creating a request queue.