The regular course registration procedure does not apply to you, since your personal study plan is your course registration document.
Your Research Master's study advisor will consult you about adding and changing courses for the upcoming semester. You will be registered for these courses by the department before the start of the course registration period.
If you are a new Research Master's student, you already enrolled yourself in Studielink when you applied for the Research Master's. If you are a current Research Master's student, make sure to re-enrol yourself in Studielink for the academic year 2021-2022 when you send your updated study plan to the study adviser. Otherwise, we will not be able to register you for your courses.
Contact the study advisers via studyadviser-cs@uva.nl