Hi @john.marcello
Sorry, but your last comment has baffle me as to how I can help. You seem to understand the basics of a conditional statement:
if (author_id == "21") :
<display the data for row 1>
endif;
Perhaps you don’t understand how to get the sub field value to compare against? You can use a function called get_sub_field to do this.
Please read the docs to learn more