Version Windows 10: You need to make sure you have java installed on your pc and duckencode.jar. when you've written a payload and save it as a .txt file, make sure you save the .txt in a folder that also contains the duckencoder.jar then when you are looking at both the .txt file and duckencoder.jar, you can hold "shift" and right click till you see "Open Powershell window here". this will pop up powershell, once it's loaded up, type in cmd and press "Enter" and then you can encode that .txt file into an inject.bin.
To do this:
you should still have powershell up and have already typed cmd and pressed enter.
type in: java -jar duckencoder.jar -i WhateverYouNamedYourScript.txt
then hit Enter and you will see the inject.bin then you can move the inject.bin to your SD card. BTW after typing in "du" for the duckencoder.jar, you can just hit Tab and it will autofill in the rest of "duckencoder.jar" same with whatever your .txt is
BTW here is the payload you can use:) just edit the part after STRING to whatever you want.
DELAY 1000
WINDOWS r
DELAY 100
STRING notepad
ENTER
DELAY 200
STRING Hello There.