There are several places in these tutorials that require you to do an activity before the Next button (or in some cases a blue arrow) will appear. Check to make sure you've completed all the pieces of the activity (if you go very quickly, sometimes the tutorial won't "count" something that you've done as complete).
If that doesn't solve the problem, try refreshing the screen (the tutorial will prompt you to pick up where you left off). If you refresh, it is best to go back to the beginning of the section you are working on to ensure that Schoology captured all of your answers.
If the issue persists, please email the issue to research.help@wheaton.edu, and we will try to resolve the problem.