How to stop populating the date field once it is populated

mk116 Posts 1 Registration date Friday July 22, 2016 Status Member Last seen July 22, 2016 - Jul 22, 2016 at 03:11 AM
I have a date field in google sheets that I populate with today() when I put in data, the problem is that the following day those fields populate again to the current day. how do I stop the population once it populates below is the sample code