Every university can only accept so many of those who apply. Most of those applying have the same qualifications but some have something more. They will obviously be the ones chosen first, then they will look for anything that will make the others stand out from the group. Finaly they will fill the list from. Those who are equally qualified by whatever criteria they choose.
Say the school will be able to take 100 new students. The first choices number 15. Then the next rank will add 25. That leaves 60 places to be filled by whatever criteria they choose from those who on paper are equally qualified. The choice of those 60 can be any one they choose with no preference stated. Then every other applicant will either be told they are on a list if any of the above drop out they will take that spot or told they are not accepted. Those who do not make either list will have to apply elsewhere.
