To add a Taiga user as a Watcher of a Task, go to the details page of that Task, and then follow these steps:
On the Sidebar, click + ADD WATCHERS.
Note: To add yourself as a watcher, click WATCH.
This action opens the Add watchers form.
On the Add watchers form, search for a user and then click the name of that user.
The user you have selected is added to the WATCHERS list on the details page of that Task.
Note: To remove any user from the WATCHERS list, position your pointer over the name of that user and then on the right side, click and confirm your action.