First, prepare your brownie batter by following the directions on the box. Then crush at least one row of Oreos (I did this by putting them in a large plastic bag and crushing them with the remote - it was the closest thing to me when I was catching up on Smash)
Next stir into the prepared brownie batter half of the crushed Oreos and pour batter into a prepared pan.
Also, I am sorry I don't have a picture of what the brownies look like when they are cut into squares. They disappeared quickly - a good sign.
Find this recipe and others on my What's Cookin' page.