Where to set front page columns?

I have just taken over supporting this site as a volunteer. It had not been updated in quite some time, so I did a bunch of theme and wordpress updates. But the volunteer who has been updating the site, can no longer find the way to set the images and text for the columns, and I can’t figure it out either. CSS indicates I’m talking about front-columns, and column1, column2, column3, and column4. He says he previously set them in appearance->mantra settings. But I don’t see anything there or elsewhere.

I know this should probably be something obvious. But could someone please point me in the right direction. I’m guessing an update changed it, but can’t find anything in your forums pointing me to the right spot.

Thanks so much in advance for you assistance.