The HackEDU Leaderboard is directly tied to points awarded for either Coding or Hacking Challenges. These are designed to give learners a challenge after they have completed our foundational courses. If your learners have not completed any of the Challenges the Leaderboard will be empty.
For more info on our Challenges/Leaderboard and how you can take advantage of them, you can check out this article: http://help.hackedu.com/en/articles/5027376-does-hackedu-have-gamification