During the campaign, you will encounter Konrad in three missions. In each of these three missions, you have the choice to pronounce either a "reprimand" or a "praise" to Konrad. To get this achievement you have to praise each time.

After you have finished the campaign you need to go to the parking lot of the police station and you can see Konrad waiting for you. Now you just need to talk to him. What will happen after that I won't tell you.