@Tony1163
First up check your hosting inbox - if it is a message with the status ' request' - here you have 24 hours to confirm or decline a booking request.
If you go to your airbnb hosting profile and click 'reservations' on the top bar, you will see a list of upcoming reservations with the status of the reservation, usually it should be 'confirmed' or 'upcoming'.
Sometimes if a payment hasn't gone through or if further guest verification is required by airbnb, it is notified here, and on your calendar it is also recorded. The guest will get emails regarding further action to take before a booking is confirmed.
You can also check the guide below on general notification troubleshooting
https://www.airbnb.com/help/article/225/why-didnt-i-get-my-email-notification
One thing to note, it can be a brassed neck scam attempt, to get access to your property without paying. Don't let anyone in, believe plausible stories, or give details on check-in without first seeing a confirmed notification in your hosting inbox. Especially if the booking is an imminent one.
If you cannot see any trace and the booker is insistent, advise the booker to contact airbnb help.