If you own, or are a member of, multiple workspaces, it can be tricky to keep track of not only your own tasks, but tasks you're subscribed to. The best way to stay up to date with everything going on across your workspaces is to use the Overview Space.
The Overview is a more focused, personalized space with a Favorites section dedicated to lists and tasks that you're subscribed to. To clarify what workspace each list or task belongs to, the name of its workspace is prepended to its name.
To open the Overview workspace, click the globe icon at the top of the workspace switcher on the left side of the screen.
Once in the Overview, you can work in the several different lists offered in Favorites, including the Dashboard, Calendar, My Tasks, Subscribed, and Delegated. Lists that you or other users have created do not appear in the Overview workspace's sidebar, though tasks in lists you are subscribed to will appear in one of the various Favorites lists.
Like your other workspaces, you can create tasks in Overview, you just need to indicate in the task form which workspace the task should be added to. Editing, commenting and completing tasks are all the same as in other workspaces.