Here is the practical update on how to get the e-referral no and the code for the vaccination against Covid-19:

visit the Polish Government page here

• have the PESEL number
• find the place where you could be registered for the vaccination at https://pacjent.erejestracja.ezdrowie.gov.pl/auth and register there via the helpline
  or/and:
• have the bank account in the bank in Poland and make sure you have provided them with the data: id no, PESEL no and the email address and when you visit the registration point you could use this bank account either.
• info in English from Study in Poland web page