You created a task board and added tasks, but you do not see the tasks on your main task list or your dashboard.
Only task board tasks that have an assignee or a due date will appear on the main task list or your dashboard. This is to prevent your task list from getting too long and unruly if you have a lot of task boards!
If you want a task from a task board to show up on the main task list, click on the task in the task board to edit it. From there, assign it to yourself and/or add a due date. After refreshing your task list, you should now see the task appear.