Additional features, settings, or issues not covered by specific Microsoft Teams categories
Hi JEDI_KNIGHT,
Based on your description, you can select User an existing plan to choose an existing Planner plan to add to a tab in this channel. you can follow the link below for more details:
If you have followed the steps but cannot find your existing plan, could you please provide a screenshot of it? And you can also go to Teams web version and check it.
Regards,
Carlos