2D modelling of four core cable

Hi, I am new to comsol so forgive any ignorance I show.

I am trying to invesigate the electrical characteristics of a four core LV cable by using a 2d model. So far I have been able to build the geomtry and add the material properties but am having difficulty in adding the circuit aspect, injecting currents etc., how should I go about this?

I built my model using magnetic fields physics as I want to investigate induction and induced currents.

Thanks