To configure administrator profiles go to System > Admin > Admin Profiles. You can only assign one profile to an administrator user.

On the New Admin Profile page, you define the components of FortiOS that will be available to view and/or edit. For example, if you configure a profile so that the administrator can only access the firewall components, when an administrator with that profile logs into the FortiGate unit, they will only be able to view and edit any firewall components including policies, addresses, schedules and any other settings that directly affect security policies.