What are the steps to building a house?

Richard Hannay, the protagonist and narrator, an expatriated Scot, returns from a long stay in Southern Africa to his new home, a flat in London. One night he is buttonholed by a stranger, a well-travelled American, who claims to be in fear for his life. The man appears to know of an anarchist plot to destabilise Europe, beginning with a plan to assassinate the Greek Premier, Karolides, during his forthcoming visit to London. He reveals his name to be Franklin P. Scudder. Hannay lets Scudder hide in his flat, and returns later the next day to find that another man has been found shot dead in the same building, apparently a suicide. Four days later Hannay returns home to find Scudder dead with a knife through his heart.