Connect the 40-pin on the 5" TFT display to the FPC extension board with the copper side facing the back of the board.
Insert the 40-pin FPC extension cable to the 40-pin connector on the TFP401 display driver by using your fingers to open the latch and inserting the cable with the blue tape facing down - silver pads facing up.
Measure two 30AWG wires for connecting the TFP401 display driver to the PowerBoost 500C. Strip and tin the ends of each wire. Solder the wires to the 5V and GND pins on the TFP401 display driver to the 5V and GND pins on the PowerBoost500C.
Plug in the JST connector from the Lithium Polymer battery to the JST port on the PowerBoost 500C.
Insert the microSD card with RetroPi image to the Raspberry Pi.
Connect the HDMI cable to the TFP401 display driver and an HDMI device (like your computer or Raspberry Pi with powered connection).
Turn on slide switch to power circuit. The display and driver should power on and show initial boot.
If the components do not power on, double check your wiring.
Power down the Pi, turn off the power switch and disconnect the battery from the PowerBoost500C. Disconnect the 40-pin FPC cable from the FPC extension board - but leave the ribbon cable connected to the display driver. On to the next steps!