How to connect netlify project to own domain

Dear Forum, I just built a website for the first time for my work. I decided to deploy it via netlify which worked perfectly. I am now trying to connect it to the domain www.societeberlin.com which is hosted on a kas server. I have tried doing it the way it is suggested in the application, but it does not seem to work. Has anyone ever connected netlify to a kas server hosted page and can suggest a solution? As I am completely new in this space so I need you to explain in simple terms please. Thank you and best, Anna