People and departments
Who you assign assets to, and the teams they belong to.
Persons
Persons are people you assign assets to. They are not always members. A contractor who never signs in still needs a person record so checkout and history have a name.
Departments
Departments are teams inside the Organisation. You can assign an asset, checkout, or reservation to a department as well as (or instead of) a person.
Both lists live under Setup. The trial allows 100 persons and 50 departments.