Assigning a RIO Plan User licence to any user will allow them to see and manage resources and also view the Planner.
As an Administrator, go to the RIO Functions App and navigate to Setup > Quick search Installed Packages. Find the RIO Plan line and select Manage Licenses.
Click on Add Users
Check the Action box for selected users being assigned to the package licenses. Once all relevant users have been selected, click the add button to finish.