Slide the logic board towards the dock connector and out of the iPhone.
When replacing the logic board after installing battery, connect the camera to the logic board before inserting it into the case. Then make sure to set the top section of the logic board (where the SIM tray is) in place before settling the rest of the board in place. This is important, as sometimes the SIM card slot will not align into place. Once the top section is in place, the bottom section can be maneuvered into place. You will know the logic board is correctly installed when the SIM tray is aligned with the opening in the iPhone case and the camera module seats neatly into its place.