Hi @dksmith!
We are still in the process of updating our Guide articles regarding some of the new features and functionalities released in Asana and we are hoping to fix this soon! Apologies for the inconvenience. In the meantime, if you have any questions, don’t hesitate to reach out in the Forum. We’ll be more than happy to assist you further!
Regarding your question, it is currently not possible to choose which Custom Fields to show in the Task Board view. If it’s Ok with you, I’m moving your post to the #productfeedback category, to allow other users to vote for this feature request. I’ve slightly edited the title to make it more discoverable. Please, don’t forget to upvote it! 