The thread under launched suggests a rule set up to add the start date of the date a task is added to the section (this thread [Rules] Set a start date based on the date the task was moved to another column) but I’ve followed the exact rule set up and it’s not working. The best I’ve been able to do is get a due date to be the date added to the section (I’m new to rules and fairly new to Asana)
If there is just 1 date, the trigger date, then the the system doesn’t need a start date because its the same as the due date.
To get the start date added too, you would need a range. You could add this if the task has a set number of days it is open. the below screen shot shows a setup where the due date is 2 days after the start date. This then utilises both the start and end date within the due date field.