How can i add control of a local relay?

[devicemodder]

what part of the code can I modify to add the relay function of a smartplug plug that I installed this on?

Ie, I would like to add a toggle to the web page/serial to toggle the relay that controls the outlet and be able to use
the pushbutton to also control said relay in the plug. How easy would that be to do with the deauth
code?