From within the User Details section, clicking on the Roles tab allows you to assign roles to a User.
Roles administration is explained in more detail in the Roles section, however, you can assign Roles to a user from the Users dialogue.
You will be shown the Available Roles as a searchable list, e.g. IT Administrator.
Tick the role or roles you wish to add to a user. Select the arrow to move the roles from Available to Assigned
To remove roles from a user, select the Roles tab and choose the Role you wish to remove.
Select the role and click the arrow to move the role from "Assigned" to "Available".
This will remove the role from the User. It can be added again at any time.
As the change is immediate, there is no success dialogue informing you that your role has been assigned or unassigned, but your role should immediately appear in the Assigned Roles list.