Using Todo with Getting Things Done

After deciding to get back on the Getting Things Done wagon recently I found that OneNote for the Mac doesn't allow custom tags so wasn't going to work. So my choice is limited to Outlook, Microsoft Planner and Microsoft Todo.

I tried using Outlook before and found it clunky and not very mobile-friendly on my other devices. So are there any guides to setting up a GTD system using either Planner or Todo? A search online left me a bit confused.