I didn’t try to add anything to either file. I was using the free version of Yoast previously, and when I upgraded to a paid Monster Insights account, AIOSEO was also installed. I had heard good things, so I decided to try it out. It immediately didn’t like the htaccess and robots files I have been using for a long time with Yoast – I have no idea what line(s) AIOSEO doesn’t like.