First greenhouse build

I was looking at different greenhouse kits and I decided to look around for my materials. In the end I only had to purchase the plastic and the staple gun. All in for $35 right now. The plastic is only 3.5 mil, but I live in the very southwest of the U.S. I know my next upgrade will be a thicker plastic, but I think this should work well for the time being. I do plan to continue to upgrade it. Making a door, improving ventilation and circulation. I also welcome recommendations. Thank you for your time and advice/recommendations and/or questions.