Receiving a notification of admission upon a successful application does not mean that you can take up corresponding studies. This notification only confirms to you that your desired higher education institution has reserved you a place in the course of your choice. In order to actually make use of this place, however, you have to go to the higher education institution previously in person within the set period taking any required documents with you and apply for enrolment.
Precise terms and conditions concerning your enrolment may not only be seen on the homepage of your future higher education institution but also in your notification of admission. There you will also find any applicable dates and deadlines.