Cincy Truck Build from Scratch I-yi-yi

Ok Guys and Gals I have had my 1996 Utilimaster ( 16x7x7 cargo) for 2 weeks I have done a lot of reading and had my eyes opened to lots of stuff on this forum, things I hadn't thought about. But anyway here goes. I have attached a sketch of my layout, I uninstalled the hanging racks in my cargo area. I have been searching for and gathering my equipment. I plan to have FRP smooth walls on the cold side and stainless steel on the hot walls. I'm going to insulate between my existing metal studs with 1/2" foam board, and go over that with the thinnest board I can find ( 1/4" osb board at home depot) to keep from losing inches where I might need them down the line. Let me know what you think and where I went wrong. I have never taken on a project like this. I know nothing about welding, engines, making parts, etc. all I know is I can cook my azzzz off and people love my food. Outside of that I am in the weeds. Help is much appreciated.Can someone also tell me how to change my pic size so i can insert them here????? Thanks in advance!!!