how to fix Google structured data errors : missing author and updated

my errors are as belows: 1) missing author and updated - (in details, these errors are from the 3 column articles below. Google 'd like to have author and updated for each article in this page) 2) missing author - I have tried many times to paste the code in single.php or page.php or content-xx.php but these could not solve. Thank you very much in advance. Ranchana