Your mobile app is dependent on what device you have. It will only show you the footage if your device is capable of sharing this.
For Fly12, you need to connect via WiFi to access your footage. For CE units, you will need to use the OTG feature and connect your device or SD card to your phone before you can review your footage.
Note: For older models with no app connectivity, you can review your footage through your desktop computer. You may use the desktop app for editing.