Thanks for reaching out.
Please note that only a Workspace admin can edit or delete boards (more about permissions can be found here - https://success.clarizen.com/hc/en-us/articles/360026733333).
Members should be able to add tasks to any board.
We have a temporary issue in which the "new task" button is disabled in some scenarios. A fix for this issue will be deployed later today.
Meanwhile, please have them try add tasks from the Stage itself or from the grid, and let us know if you run into any issue.