You can find here a list of necessary and useful documents and application forms.
Application form for Visa D1.1
Necessary documents for enrolment of foreign students
Application form for Tax Registration Number
Contact e-mail and address of the Decentralized Administration of Attica
Email of Immigration Service Directorates
Documents to carry with your "Blue Certificate"
Solemn declaration of the Tax Representative
Authorization to assign TIN Number and Key Code
Instructions on how to obtain your AFM and your username and password