How do I get the key to the property?

Every manager does things a bit differently.

Some options include:

Manager mails you a key a week or two before stay.

Manager lives on premise or close by & will personally give you a key, sometimes bearing welcome gifts.

Some have lockboxes

A lot of managers are going to keyless systems & will give you a code to check in & out. The code expires at check out time. So make sure you don't get locked out if you are tardy checking out!