Pro tip: don’t transfer your screens from 530 to 840.
If you do, you’ll end up with a Default Workout screen:
and not be able to edit the bottom two fields.
After my 2nd ride this morning, I reset and deleted all data. Now I can edit those bottom two fields:
Wanted to mention that because I searched the Garmin 1040 forum and nobody answered the question.
Now off to complain to Garmin about the ridiculously stupid step distance and vertical red/yellow/green power target (needs to be horizontal like on 530).