[Fire TV Original Android Development] retyre:
Let me clarify the first few steps in the OP (this is where I expect most of the challenge to be):

-- This is what you will need to begin: Arduino Due (this is what I have), HDMI breakout board (this is what I used because I have the pendant; if you have the cube, you will need a male HDMI as in the wiki; if you have the pendant, you can also use the male with a coupler), M/M jumper wire (this is what I used), and a Linux box (I have Ubuntu 16.04.5 LTS installed).

To install the Arduino IDE and upload the sketch, follow these steps in sequence:

1. Download the Arduino IDE. (If you use v1.6.1 or earlier, you don't have to install the Due board separately.) For Linux, download v1.6.1 from here. (Note: You don't have to do this in Linux. For Windows, use this.)

General note for Linux: It might just be easier to run everything as root (to sidestep permission issues): use sudo. As an example, sudo ./arduino to start the Arduino IDE instead of just ./arduino.

2. Connect the Due to your PC's USB port, install the Windows driver (located inside arduino-1.6.1-windows.zip; no driver needed for Linux), and choose the correct Board (Native or Programming depending on which is connected; I usually use the Programming port) and Port.

3. Download and extract the archive in the OP (FireFU.tgz).

4. Upload the sketch (hdmi_arduino.ino, from the archive) to the Due. To do this, open hdmi_arduino.ino from File and choose Upload from Sketch or just click the right-arrow. Pull up the separator at the bottom to make it easier to view the progress window.

6. Confirm that the upload and verification are successful.

You will need Linux from this point forward.

5. Check to see whether libusb is already installed:

dpkg -l libusb*

If not, install it:

sudo apt-get install libusb-1.0-0

6. Add the proper udev rules for Amlogic and fastboot as described in the OP's link. If you do not know how to manually add rules in /etc/udev/rules.d/, do the following:

-- To automate the udev rule for Amlogic (from here):

sudo apt-get install git
git clone https://github.com/khadas/utils
cd utils
./INSTALL

This will write the Amlogic rule (/etc/udev/rules.d/70-*). To add the fastboot rule, open the file (70-*) in an editor, copy-and-paste the line for Amlogic, and change the vendor and product id to match that for fastboot.

To manually add the udev rules, create a new file (say, 70-firetv3.rules) with the following in it:

SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ATTR{idVendor}=="1b8e", ATTR{idProduct}=="c003", MODE:="0666"

SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ATTR{idVendor}=="18d1", ATTR{idProduct}=="0d02", MODE:="0666"

-- Install fastboot and adb:

sudo apt-get install android-tools-adb android-tools-fastboot

7. Reboot for the rules to take effect.

8. Connect the following in order:

-- jumper wire to SCL, SDA, and GND on the Due ... and to the breakout board (as described in the wiki)

-- AFTV3's male HDMI to the breakout board's female HDMI (or the cube's female HDMI to the breakout board's male HDMI)

-- power to the Due (I use external power, but connecting it to USB power should work just as well)

-- micro USB to the AFTV3

-- other end of the micro USB to the Linux box's USB port

9. Check whether Amlogic, Inc. shows up:

lsusb

10. If it does, you're more than halfway there. If it does not, disconnect everything but the jumper wire and repeat step 8.