It's actually quite simple. First of all, when Zhang Hui's story ends, you will meet an old couple at the vent. After the talk, you can lead them to stay in the security room. After the two were rescued, they set out from the shopping mall, and the main task took place in the warehouse and went to the central square, which is the parking lot in the west. However, there are many zombies here, but they can be hit by cars. Just do some training, and then take a bus through the central warehouse. In the south, you can find the way to the next floor, so you can return to the shopping mall from the Song escape passage. Starting from a dictionary is the best choice to reach all fields.