how can I apply for NIT Shibpur?
Since the mains results are declared and guys who has cleared in that can sit in JOSSA. But if a person wants to do counselling through JOSSA then he has to wait until the IIT advance results are declared. You can see the JOSSA schedule from here which have all the details,
https://josaa.nic.in/webinfo/File/GetFile?FileId=3&LangId=P