Subtasks and viewing in Lists and/or Timelines

Hi @Paul_Gordon and welcome to the Forum!

Because subtasks don’t currently inherit their parent tasks project, they do not not show up on your timeline, unless you manually add them to the Project using the Tab+P shortcut. You can learn more about this in the following guide article: How to Use Asana subtasks | Product guide • Asana Product Guide

The best advice I can give you is to add your subtasks to their parent task project using the TAB+P shortcut > once you do this, subtasks will show on your Timeline (providing they have a due date). But by doing this, subtasks will also show in your task list; so to avoid any confusion, I’d recommend creating a Section call subtasks and nest all your subtasks under this section so they don’t bother you in your tasks list view.

Hope this helps!