On this page of the Disco Elysium guide, you will find a walkthrough for the Interview cafeteria manager quest.
Your objective in the Interview cafeteria manager quest in Disco Elysium is to talk with the manager of the cafe at the Whirling-In-Rags hotel. The man may know something about the murder that was committed in the yard behind the building. The quest will be available after the first conversation with Kim.
Walk up to the bar counter and talk to Garte - the cafeteria manager. The man will not be able to help – at the time of the crime he was in another district, and he was not the one who informed the police. Garte will mention Sylva Malaiika, a former cafe worker, and say she may be the one who called – this activates Who made the call reporting the crime? quest.