I got some answers for ya here :D
Here is the back of an Auber PID:
View attachment 641570
1. The cord you see coming out plugs into your home's outlet to get power from the wall to the PID
2. The socket labeled "Output" is where you plug your MES cord.
With the MES rewire the MES is altered so that it's cord will feed power directly to the heating element.
Now the PID can take power from your home and feed it to the MES via that socket where you plug the rewired MES cord.
3. The little round socket labeled "Sensor" is where you plug a temperature probe that will sense heat.
You will run the temp probe into your smoker/toaster/device and clip it somewhere so that it can measure the temperature inside the smoker/device.
When set a temperature you want to hit, like 275F, the PID will use that temp probe to read the heat.
The PID will then feed power from the wall to the smoker until it hits and holds the set temp.
The PID will cut power on/off to the smoker however it sees fit to hit and hold the set temp you entered.
That is all the magic. So in short everything is hooked up like :
Wall Socket-> PID->rewired MES (with PID reading temp inside MES) .
You never wire the PID directly into the device.
As you can see from the image everything can be unhooked so you can move the PID, take it inside, or use on a different device.
I drop my PID temp probe down my MES vent and clip it to the bottom of the lowest rack so I can move the temp probe if necessary. Super easy.
I hope this helps clear some things up. Ask all the questions you have and we will get it sorted out for ya :D