Complex sentence: They had both a cat and a Labrador retriever puppy, and found that when Genie first moved in she was terrified of both animals; upon seeing their puppy for the first time she immediately ran into the next room and hid.
Split into simpler sentences: They had both a cat and a Labrador retriever puppy, and when Genie first moved in she was terrified of both animals. Upon seeing their puppy for the first time she immediately ran into the next room and hid.