Insert permanent Date & Time stamp if & when another cell is populated

Hello, i have a similar requirement to this thread, with one slight extension. I need this to work for every row after the third. I.E. a3 = date, b3 = time, if c3 = amended (not necessarily empty to begin with but changed from its previous data held). Then A4,B4,C4 the same ect ect all the way down.

Can anyone show me some code that might fulfil this need?

Thank you.