Hi Dana @Admin Transformation, you (or another subscription administrator) will need to give "Planner" permissions to yourself or others who wish to use Capacity Planning.
Currently, one cannot assign planning permissions to him/herself. However, if you switch to the new users grid (in beta), you can filter the view to yourself, add the planner column and make yourself a planner from the grid. Please let me know if you'd like me to enable this for your subscription.
This may be the best approach to move forward with as we make a change allowing admins to grant this access to themselves.