This is regarding assignment.
There are some situation where things are not clear and we need to make some assumption, should we make our assumption in such a way that it makes our work easy or make an assumption that it takes care of all the possibility cases but add more work and complexities in the system design?
You may have to read the assignment again and again and make sure that any requirement is not getting missed.
Because there may be scenarios, which are not clear in the first reading but you can get idea, after going through the problem statement again and again.
Once you are sure, you are not missing any functional/non-functional requirement, then you can make assumptions.