Things will clear up as you keep reading. there is clearly the story of the four brothers and their relationship to each other and to their father, but Dostoevsky struggled with the role of the church in the life of the individual, the existence and relevance of God in man's life. Religion, especially Russian Orthodox was a huge influence in people's lives and he questions it. this novel is considered by many to be one of the most powerful Christian texts. Hope this helps.
ms. G