"An Occurrence at Owl Creek Bridge" what is the first & second section of the story about ?

The insult most likely has to do with something about Montresor's family. When Montresor is in the catacombs with Fortuanto, Fortunato takes several unconscious digs at Montresor's family. At one point he says, "Oh, I forgot, the Montresors were once a great and noble family." In other words, Montresor's family is not as noble as it once was. Then, Fortunato makes the sign of the masons, an exclusive club of prominent men of the time. Then he says, "Oh, you are not of the masons?",an obvious dig a Montresor's prestige. Montresor quickly pulls out a trowel, a tool of the common mason, or bricklayer, and says, sarcastically, "Yes. Yes, I am a mason." Of course, this is a reference to Montresor's plan to bury Fortunato alive. Poor Fortunato is totally obvious to this plan because he is so proud and also drunk.