On this page of the Disco Elysium guide, you will find a detailed walkthrough of the Get a reality lowdown quest.
You can start the Get a reality lowdown quest in Disco Elysium when talking to Lena – tell her that you have no idea where you are. The woman will suggest you to ask someone rich for a more detailed explanation of the world.
Go to the harbor in the west end of the district – you will find Joyce Messier. Talk to her about the world in which you live - You seem smart, I need someone to give me a low-down on this... reality we're in.
To pass this quest, you have to ask about at least two topics. After the first question, the task will be updated and you will need to speak to Joyce again to complete it.