When you're telling a story, you start by giving the setup for the story. This is a description of what was happening before the interesting action started. A very quick way to describe this is to say "I was (doing something), and (something happened). For example, these sentences could be used at the beginning of a short story:
I was washing the dishes, and I noticed that one of the plates had a crack in it.
I was watching TV on the couch, and my wife turned to me and said, "Guess what I heard today..."
The word "and" in these examples means "and then".