We required access details for CyberArk SCIM based connector to update the connection.
The access token is ideally dynamically generated with the auth call. In case the access token is a static value, you can generate it via postman and paste the value in "accessToken": "Basic *******"
You can refer the below documentation for cyberark and REST intergation
Unfortunately I don't have postman documentation and the steps will be different for every application. You should be able to find something on Google or can even check with the target application team.