On this page of the guide to Disco Elysium, you will find a walkthrough of the Ask Kim task to tell you about the case quest.
Your goal in Ask Kim to tell you about the case quest in Disco Elysium is to talk to Harry's partner about the investigation they are working on together.
Police officers are always well informed about the cases they are currently working on. Unfortunately, Harry suffers from amnesia. You need to slightly refresh his memory - talk to Kim and ask him for a briefing to learn more about the case you are trying to resolve together.