It should say
"Managers listed here are all employees with management responsibility - this is anyone who does not have just a trainee role (e.g. managers, admins, super admins etc.).
Add new users to this list by going to Organisation Setup > Users > Edit User and change the role from "Trainer".
Managers that appear on this list can have employees, departments and courses added to them so they get visibility to that data."
We will in time add further help panels to some other (but not all) screens such as these.