Following my previous guide, here is another tutorial as requested covering how to add your choice of payload into PS4 playground for ESP8266.
Again I use treyjazz's sample webpage for this tutorial (in 'data' folder inside PS4Exploit).
I suggest you download Notepad++ for code editing. Download and install.
So now navigate to 'data' folder. You will see bunch of files (.js and .html) in it. The webpage you see on ESP8266 is coded in 'index.html'. So find 'index.html', right-click on it, click 'Edit with Notepad++'.