If you wish to create a task list template from scratch rather than saving an existing task list as a template, you can do that from the task list templates settings.
1. Go to a workspace and select Options > Manage Task List Templates.
2. Click on New task list template.
3. Enter a name for your task list template and hit Create.
4. Enter a name for the task, add subtasks, watchers, assignees, task duration (days), description and hit Create.
5. You should now see a new task list template with the task you created. You can now apply this task list template when creating a new new task list in any workspace.