I start with the two TBD62083 chips, then the MCP23017. There should be a dot on the PCB to help with chip alignment. Next solder on the three resistors (two 47K and one 1K). If you're building the Photon PCB version, do the 2 capacitors then the VXO7805.

Solder on the 3 sets of three pin headers for the i2c address (A0, A1, and A2). You'll need to attach a jumper to each one to pull the pin high or low (chip will not work if these are left floating). The remaining header pins are optional depending on your setup. 

The board has labels for the three sets of wires from the 7-Segment display. Black wires (which are used for 12v power) can be attached in any order. The Orange and Red wires must attach to the corresponding letter position. Viewed from the BACK of the display, the wires follow this order (with "A" starting on the top center, and then "B" on the top left)

    A
    _
B |   | F
  |   |
    - <----- G
C |   | E
  | _ |
    D

Connect a micro-controller to the pins labeled GND, 5V, SDA, SCL. If you are using the Photon Board, simply connect a Particle Photon to the headers. You will also need a 12volt 500mA (or higher) power connected to drive the display. Ensure the barrel connector is CENTER POSITIVE before connecting.  The Photon board has a built in switching regulator to supply power to the Photon from the 12 volt line.