@Anni4097 This is a community centre not customer support but in answer to your questions
1) Airbnb will pay into your bank, via Paypal or via a different route depending on where you live and what you select. Payment is initiated when the guest checks in and will get to you up to a week later - Longer for your first stay.
2) Yes you have to register your bank account with Airbnb within your account
3) Depending on your cancellation policy Airbnb will refund a guest if they cancel
If you go to the Airbnb Help website and use the search function you will find most of the answers you are looking for including how you set up payment on Airbnb to go into your bank account or other payment channel.