The Selfservice offers various accounts for different services. Some of these accounts are set up automatically after the registration e.g. the RWTH Single Sign-On account, others can be added afterwards, depending on your membership of RWTH Aachen University. Therefore you first need to select the tab "Accounts and Passwords" and then “Create Account”:

If you e.g. do not yet have an RWTH Collaboration Create account, it can be selected here.