The first step of the registration is filling in this form. You will receive an email message with which you can confirm your registration. After confirmation you can login with your email address and your password.
The password you entered appears on the list of collected passwords from data leaks. It is therefore a weak password that you should not use. I advise you to choose a strong and unique password (and not to use it on other websites).
Find your ancestors and publish your family tree on Genealogie Online via https://www.genealogieonline.nl/en/