If you are on a waiting list, it means that you are qualified, but there are more qualified applicants than there are available seats. If you want to stay on the waiting list you have to accept the offer in the application portal within the given deadline.
If you accept the waiting list offer you may be offered admission at a later date if a seat opens up.
You will not receive an e-mail if your waiting list number changes, you will only receive an e-mail if you are offered admission. If you are offered admission you have to accept the new offer within the given deadline.
If you are put on a waiting list you have the right to ask for grounds of rejection.