Hello there. I would like to tell you that you must have received your login credentials in your e-mail. Application ID must be mentioned in your mail id. If you are having trouble logging in, you can write a mail to the help desk of the exam you are appearing for. the email id is mentioned on their official website. Please note that application ID is generated only when you have registered before. If you are a new user, then you need to register first and then proceed further.

I hope you found this answer helpful. Good luck for your future.