Heat Sink and Cold Plate Boundary Conditions

Hi. I've read some of the forum posts regarding a heat source inside an enclosed box.

https://forum.solidworks.com/message/186708#186708

This post was about a heat source floating inside an enclosed aluminum enclosure.
I am using the same enclosure and changing the heat source to be attached to the enclosure (see pics).
I'm hoping someone can tell me the boundary and flow simulation wizard initial setup.

If someone could please tell me how to set up the flow simulation (see pics) and boundary conditions (see pics) that would be great.

I don't know if I should enable gravity and radiation. They exist so I wanted to include them.

My heat source will be 5W and attached on the inside of the aluminum enclosure.

I know how to set up a heat source. I don't know if I need to specify the boundary between the heat source and the enclosure (metal to metal boundary). Since they are connected then I need to specify a thermal coefficient?

I'm trying to find:

how hot the enclosure gets at certain points on the enclosure.

how hot it gets inside the enclosure.

Lastly, when setting up the analysis I can choose radiation. Here I can specify a temperature..this is the outside temperature, right?

I'm hoping my pictures will make answering this post easy. Thanks.

SolidworksFlow Simulation