IBSAT is a home proctored exam and it will held in the last week of December. You should check your admit card and email that whether you have received login credentials or not. In order to give this exam you must have username and password. At the test day they will be sending you the test link and you will have to login with your username and password. If you do not have login credentials then contact their team as soon as possible but only after checking your mail and admit card properly. They will thoroughly guide you everything.