@Raymond318 The first thing you should do is review your host's cancellation policy and contact them to let them know you will not be arriving. Your host might be willing to offer a date change or some other arrangement in lieu of a full refund, but for best results I recommend that you open the conversation acknowledging the terms of the booking that you agreed to and not immediately asking to be exempted from them. Be aware that hosts are not able to refund Airbnb's service fees.
In some cases - particularly if you placed this booking before 14 March - extenuating circumstances may apply. Details here: https://www.airbnb.com/help/article/2701/extenuating-circumstances-policy-and-the-coronavirus-covid1...