How to determine the difference between a problem that involves permutations and one that involves combinations?

I know the difference between a permutation and a combination, permutations involve a specific order and combinations do not involve a specific order. But sometimes, it isn’t clear whether it’s a permutation or a combination. For instance: “Fifteen students ask to visit a college admissions counselor. Each visit includes one student. In how many ways can ten time slots be assigned?”, taken from my textbook. After some perusing, I think I may have figured out why it is a permutation, the book told me from the start, and that’s because it is one student, and the time element denotes an order. What are certain key things (i.e. time, quantity) to look for to distinguish this when math is out to get me?