A record picker by itself cannot trigger an automation. You can trigger an automation from a button element with a run automation action. Or you can trigger an automation from the user editing a field value for the record.
Thank you, Kuovonne.
So, there is no way to trigger some processing depending on the record selected on the list.
For example, I want to automatically change a status field in records in another (child) table, that are linked to the record clicked in the picker (parent table).
Do you know a way to do this, from an interface?