You can see which licences are needed by going into the Page Parameters option in the Profile menu (top right-hand side of the Workbench screen).
The Page Licences tab will tell you which role-based licences, site licences and permissions are needed.
You only need one role-based licence, but you may also need to have a Site Licence and a Permission.
For example to see the requirements for the Plant Location Groups page: you would need ANY ONE OF System Admin, Finance, Data Entry or Job Costing, AND the Plant Management site licence AND the Plant Administrator role.
Alternatively, in the Licence Matrix screen on the Purchased Licences tab, click any Licence Name link to display a report for that licence.