Sorry, @Allen, just one more thing! I'm still struggling to get to a list of all of the custom fields. I've tried clicking on explorer and looking for the custom fields category in the drop-down, but it's not one of the options:
Beyond that, I'm getting stuck. I went back to the link you originally posted and substituted workspace-id for the actual number, then pasted that into Chrome, but that gave me an error message so I'm sure I haven't done that correctly either.
I'm really not very good at this, so if you could walk me through it as though teaching a complete beginner, I'd really appreciate it.
Sorry for taking up so much of your time!