CSAB means central seat allocation board.after the jossa councelling rounds were completed then a special round is applied and that is by CSAB .you have to pay for applying that round .the candidates will have to go to the official website of CSAB NUET 2020 and use their JEE Main 2020 application form number and password to register. And councelling process continues.for the councelling purpose use the link college predictor https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer