"When a Button is Clicked" and "Trigger an Automation" button

I’m trying to use the (new-ish?) “When a Button is Clicked” automation trigger. The button is on an Interface in the same table as the Automation.

On the automation, the trigger’s configuration instructions are as follows;

This trigger is not currently associated with any buttons in an interface.
To connect:
Open an interface
Create or select a button
Select “Trigger an automation” under “Button Type” in the properties pane
Choose this automation from the list

In the interface, I have the “Button type” set to “Run Automation”
Under the “Table - Source” it says “Unconfigured Source,” with no options for the source.
The Automation option is grayed out.

So it seems like the button can’t find the Automation, but the Automation can’t be turned on because I need to fix the configuration…

Has anyone encountered this? I’m guessing I’m missing something quite simple but this is my first foray into the Interface Designer with Automations.

Thanks in advance.

Hmm, do you have any Record Picker elements in your interface? Those usually work as sources for me here