Opinions on how to modify coop for winter

I have made several coops and have learned with each one how to make them better. So I need to revisit my 1st coop and make sure is it suitable for winter. It is 4X6 and 5' tall. It has a 4x6 porch which I will incorporate with the existing coop to make it 8x6. I have pictures of what it is and how it looks now. Give me some suggestions. It used to be covered porch for a dog house. I need to have ideas on improvements that would be the best value for my money. I have a local metal shop and can get sheets of corrugated metal pretty cheap. I have a circular saw, drill, hammer, nails, screws, and related tools for improvements. I do not have a router or table saw. I also have a stack of pallets and scrap wood and a few sheets of metal handy.

Original condition before chicken coop


Wall, I have vents like this on the other side too. You can see the covered porch in the back.


Run. Do I need to cover with plastic, tarp, straw bales, metal? Would that help any or would I be wasting my money.


Finished with bantam coop to the right. Nest box in the front with big wire covered window on top of nest box. The board (shutter) on top can be let up and down. Do I need to put plastic over the window or just leave it. Window faces North.


Covered porch and pop door.