I simply want to update a field via a Lookup.
Object Customer Master has a lookup to standard object Account (CM is a related list on the Account layouts as well). I have a custom Lookup field on the Account.
I want to stamp the ID of the Customer Master to the Account.
(there "will never be" more than one record despite the many-to-one possibility via Lookup - but EVEN IF THERE WERE, I want the CM record being touched to set it's ID into the Account custom lookup field)
In my screenshot, note that field picklist at the bottom (red). It is showing me fields from the child (Customer Master), NOT the lookup to Account (note above in green, I've picked what I want to update).
The verbiage is bad enough (because it calls it "record type", and on the screen where you select it, you are selecting a FIELD on the RECORD you want to update, bu the screen asks you what RECORD you want to update.
I am at a complete loss. Nothing is making sense.
How do you update a field on the lookup record using Process Builder? Every search I come up with dances around this without an actual example! I'd actually like it if someone points out something I spent an hour missing at this point. Much rather have a workflow, but... (sigh)