Use My Tasks in the Account Menu to monitor deadlines and events in the site that you're currently viewing. If you open My Tasks while viewing your Home site, you can also manually add personal tasks that will be visible only to you.
My Tasks in the Account Menu shares information with the My Tasks area in the Dashboard tool.
Click My Tasks to unfurl the tasks information for the site you're currently viewing.
See How do I add a task to the Tasks widget? for information about adding tasks.