I am a Microbiologist. There are three ways for a contagion to spread, by contact, by droplets or through the air. This novel coronavirus spreads through droplets. This means that the droplets fall to the ground even with a cough at about the 5 foot mark. This is the reason for social distancing. As I know you have heard, the most important thing that anyone can do is to wash their hands thoroughly before you touch your nose, mouth or eyes after you have touched something that could transfer the virus. Wash you hands every time you come inside after touching something outside. A good way to do this is to sing Happy Birthday twice while you wash your hands. Since this is a new virus everyone can get it. Therefore, everyone has to protect themselves and others.
Imagine how many people touched a door knob or a hand rail and you can understand why you have to wash your hands. It is not only them, but all the people who have touched something before they touched it and all of that gets passed on. Try an experiment. Pass an item, anything, a ball, a book, and try to keep track of all its contacts. Remember all those before you and it keeps multiplying. Then you get an idea of how many people you are in contact with without even realizing it.
Wash your hands often and stay 6 feet away from people not in you household and be safe.