Here are the steps to add a scorecard to a competition:

1. Once you get to the third step of creating competition, select Scorecard in the "Select Task".
2. Give a name to the task
3. Assign points for the task
4. Set a start and end date of the task

Below is a screenshot of adding a scorecard to a competition:

Then, click on the "Create" button.  The scorecard will be created and added to the competition successfully.