This means that you will be provided admission to your course based on your last qualified examination. Suppose you want to take admission in BSc then you will provided admission as per your 10+2 results. This implies that all the students who will apply for the course will be sequenced and ranked as per there 10+2 marks and will be provided admission serially.

Also if you don't get a chance in the first list then there will be subsequent lists until and unless the vacant seats are complete.

I hope my answer helps. All the very best for your future endeavors!