There are a couple of web sites that I went off of for mine. I'll try to get some pics and get the links together.Perty simple really.
My first one,(the big boy) was an old out of use ceramic kiln. Ya gotta remove the coils,and switches,install a new coil or coils,depending on the size (with the right amount of olms) and new switches. Ya have to also have a mutimeter with a high temp probe,unless you are lucky enough to have a perometer.
I'll work on it.