And I thought that I would just add a few suggestions if you will; I used masonite 4x8 sheets. Has a lumber look on the outside and has nice jointing cuts. Masonite is pre primed and with paint, you will get a life time of use from it. But, where you screw it in or nail it be sure to caulk those areas well. The skin has been exposed and rot will occure there. Keep the masonite off the ground also.
secondly, use that double door system and have the doors hung on piano hinges. Will work great and they will not settle and lag.
Be sure that the pitch of the roof is great enough to cause proper water and runoff.
For security make all studs 16 inch OC and use fire blocks, they strengthen the walls and also come in hands as shelves.
Fastening to cement, drill down deep holes and use that product from Red Head to fasten the sole plate to the concrete.
Install soffett vents around at the top for ventilation.