Hi @Roger324 ,
instant booking is a default within the hosting system.
If you go into the listing-> booking requirements-> how guests can book
you Can change it to all guests must send reservation requests.
whist you are at it I would check booking requirements, check in/out times, turnover times and cut off time time for new reservations.... as to fit your preference. This may put you down in terms of your listing positioning but it’s besr whilst you are learning.
Regarding those reservations I would suggest you contact Airbnb and blame it down to “rookie mistake/not knowing”.
good luck and happy hosting !

Yadira