Crime and Punishment is not hard to understand, but it is a long novel of ideas, full of Russian names and dense conversations, and it is worth reading knowing this. The plot, by contrast, is direct: a crime right away in Part One and then the magistrate's siege, at the pace of a detective story turned inside out.
It has six parts and an epilogue, 41 numbered chapters, and it was serialized through 1866: each part closes on a point of tension. Part One, in seven chapters, lays out the whole problem: the poor student, the old pawnbroker, the dream of the mare, and the double murder. The narrator never leaves Raskolnikov's side, which helps in following the story.
What takes effort are three things. The names: Raskolnikov is Rodion Romanovich, Rodya to his mother and sister, and his sister Avdotya Romanovna is also Dunya and Dunechka. The conversations: the drunkard Marmeladov pours out his family's story in the tavern, and the magistrate Porfiry wraps the suspect in digressions about his own apartment and his own health. And the ideas: the theory of ordinary and extraordinary people is set out in full in Chapter V of Part Three and demands attention.
A few tips: make a list of characters in the first pages, read Part One all at once, and prefer a translation made directly from the Russian. There are two possible reactions: those who lose themselves in the names and the monologues find the book heavy; those who accept its fevered rhythm of argument and discussion find that this is precisely what makes it a detective novel unlike any other. The text supports both.