How to start writing a UMAT for Thermoelectric material

Hi,

I recently statrted using ABAQUS. I started writing subroutines few days ago and I have written few basic subroutines such as Istothermal Istoropic material. I need to come up with a Umat code for thermoelectric material. I dont know where and how start working on it. I will be really helpful if someone could share their ideas with me.

Thanks,

Deepak