Some rewards will be sent through in game mail and you need to claim it at the Mail box. Touch the envelope icon in the upper right corner of the main screen.
It is divided into two parts : the first section being devoted to a sketch of the Colony and Protectorate and a description (necessarily fragmentary) of the peoples;.
The Mailbox is devided into two sections: the first section for mails with rewards & compenstaions; the second section for mails from friends.
Please note that mail has its expiration date. Be sure to accept rewards before it is expired.