@Gil-Joyce0
don't ever cancel reservation on Airbnb bc you will be penalized with blocked dates, f50-100$ fee, automated review and you will lose the superhost status for a year. your search position can also be affected.
If you have very good reasons for cancellation without penalty then you should contact Airbnb and ask them to cancel for you. It could be illnes or natural disaster or other extenuating circumstances or.... if you have instant booking turned on, if your guest doesn't respond to your messages , are rude or intend to break your house rules.
If you can not plan long time in advance you can open your calendar for next 3 or 6 months only. Or even less but then you have to block/unblock it manually. While your calendar is open for bookings , instant or not, you should be in wifi zone, able to receive notifications and answer to messages.