UseCase responsibilities

What can subclasses of UseCase do? What can't they do? In this project use cases are atomic tasks used to simply obtain data, but what about decision making, where does that belong?
Example 1: I have a collection of items and lazy loading. Is there one UseCase handling all pagination logic and calling necessary repository methods, or are there multiple UseCases and something (presenter?) orchestrating them?
Example 2: after executing a UseCase, based on its response we make a decision on what UseCase to call next. Again, where is this decision made?