To update a task, select that option from the right side options menu.
This takes you to a page where you can make your changes and, when finished, click the "Update this Task" button. If you click the "Start Over" button this will clear the form of any changes you've made without updating the task.
To delete a task, select that option from the right side options menu.
This opens a page that lists the task and asks the question "Do you want to delete this Task?" If the answer is yes, click the "Delete" button at the bottom of the page. If not, click "Cancel."