1. If you are planning on using Folders, Contexts, Goals or Tags in your Task template, and you want those values to apply to the parent task and all of the subtasks, you can save some time if you specify those values in the parent task before you create the subtasks. Otherwise, you'll have to change the values for each subtask.
2. When you create the subtasks, you can use the "Add multiple tasks" feature.
3. You can't pre-populate time intervals between subtasks for non-repeating parent tasks. You can put dates but those dates won't be automatically updated when you clone the parent task. As an example, you might have a set of tasks that you do routinely but not at fixed intervals. If some of those tasks must be done at specific times over the course of a few days, it will take some additional effort to stipulate the schedule, even if you use a template.
4. "Task templates" seem to be best for checklists.
5. For simple checklists, you might find it easier to add the items in the task's Notes instead of creating subtasks.
6. The templates (parent task and subtasks) are still part of all your tasks so you'll want to somehow filter them out of your list of active tasks. See How do filters work?
7. You'll probably want to assign your templates to a Context or Folder called "Templates" so that you can find them easily. Or you could create a Saved Search based on some other variable. The Quick Search function won't work if your templates have been filtered out of your task list.
Ideally, the Templates should reside outside of your task list and they should be available when you create a new task, but you can't do this in Toodledo. Not yet, anyway.
I do what Purveyor does (there is no such thing as original thought! LOL) I make a "Text" backup" of all my templates and store them in Notes. Then, if I screw something up and use or delete my template by accident, I can use "Add multiple tasks" to recover the template structure.