Start by laying out your assembled frame on a flat surface.

Attach the NeoPixel clips to the frame with the NeoPixel mount facing out. You'll want to have them evenly spaced around the frame.

Slide the bottom corners of the frame into the two stand pieces. 

Start to insert the NeoPixel strip near where you will be placing the Pixel Trinkey. This will let you keep the NeoPixel wires short. The strip will press fit securely into the clips.

Continue to route the NeoPixels around the frame, pressing the strip into the clips.

Once you've covered the distance of the frame, align the two ends of the strip together. Determine where you want to cut the strip. Here, there was a set of contacts that aligned with the first NeoPixel, so I chose to cut there.

Cut the NeoPixel strip on the contacts between pixels.

At this point, carefully stand up the frame vertically.

Insert four M2.5 stand-offs into the front of your chosen stand side.

Mount the Raspberry Pi to the stand-offs with M2.5 screws.

Insert the Pixel Trinkey into its case.

Plug the Pixel Trinkey into the bottom USB 2.0 port on the Raspberry Pi. Insert the NeoPixel wires into the terminal block on the Pixel Trinkey:

• NeoPixel GND to Trinkey - (black wire)
• NeoPixel DIN to Trinkey D (white wire)
• NeoPixel +5V to Trinkey + (red wire)

Plug the USB capture card into a USB 3.0 port on the Raspberry Pi. You may need a USB extender if its case conflicts with the Pixel Trinkey.

That completes the assembly! Before you place it behind your display, you'll want to do a test run to make sure all of the NeoPixels are lighting up and that everything is working as expected.

After testing, you can place the frame behind your display. Make sure to line-up the frame with the edges of your display.

When you're facing the display you shouldn't be able to see any of the edges of the frame.