I spent a full day squaring up the case frame, squaring joints, re-aligning joints etc. in preparation of fastening the sheeting. The steps I use to attach a sheet are: Drill a hole in the sheet. Use the hole in the sheet to guide the drill bit for the hole in the frame. Thread the frame hole. Countersink the sheet hole. Admire work. The case with the inner front, bottom and lower back panels attached.