Getting datetime stamp for change for original status, and change in status

[edmund_chan]

Taking the Order Capture sample app as an example, I need to capture l

1. The datetime stamp when a new order is created (that will by default be an “open” status order”)
2. The datetime stamp when the same order is changed to “complete” status.

For 1. I can do it via with a column with the formula now(), but how do I get the datetime stamp when the status is changed, without overriding the original datetime stamp when the order was at “open” status?

Looking forward to any help I can get from this community