At the time of the writing of this article we do not yet have access to an Amazon Fire phone.
According to their specifications, the Amazon Fire phone runs on Amazon Fire OS v3.5 (Android based OS),
Please use the tutorial for Android 4.4.3+ to connect your Ceres Speakers to your Amazon Fire phone.
Amazon does however have this article on their website which is their instructions for pairing Bluetooth devices with Amazon Fire phones.
Please contact PreSonus Technical Support by creating a Support Ticket at My.PreSonus.com for further assistance.