For New (B.Tech., Preparatory, ASEAN Fellowship, SII Scheme, Casual Student) Students, first you have to register by click on Register link by using your eMail(registered with institute). Now your userid will be your JEE Adv. Roll No. and you will get password in your registered eMail.
For New M.Sc./M.Sc.- M.Tech. Students (except M.Sc.(DH)), first you have to register by click on Register link by using your eMail. Now your userid will be your JAM Enrollment ID and you will get password in your registered eMail.
For New PG/Diploma Students who have applied through IIT Admission Portal (https://oa.iitj.ac.in/OA_PG_ADMISSION), your userid will be your Application No. and password will be the same as on the application when you have applied for these application.