Define heat source

Hi friends

I want to simulate toaster (see link https://www.amazon.com/Chefman-Electric-Sandwich-CoolTouch-Countertop/dp/B00FVUSL3C : ). I want to measure the temperature outside the body.

I have some problems with boundary conditions.

resistance power: 900 watt

1- How to model the heat source? 

If I choose a volume heat source and enter 900 watts, would it be a right fit?

2- radiation, heat transfer coefficient, or a parameter I missed.

Is it necessary to define these parameters?

Thanks for your suggestions

Best regards,

SolidworksFlow Simulation