You can register for IBA in Studielink between 1 October and 15 January. It is not possible to register after the deadline of 15 January. Late registration is not possible under any circumstances. The Dutch government has determined this deadline and exceptions are not possible. 

After registering in Studielink, you have until 31 January to submit the RSM Online Application Form (OLAF). Only students who have registered in Studielink and submitted their application via OLAF, are considered for the programme.