Here's a quick step by step for making my 3d cot.
Import the svgs into scal and cut. The inner header is only required if you want to mask while stamping or if you need to reinforce the card. The inner side is used to hide the tabs if you want to but I havent found it necessary.
If you are making a cot with a solid headboard or kickboard now is the time to decorate. I cut the inner header purely to use as a mask while I used some peg stamps to add a patterned border. While I was stamping I also decorated the inner panel.
Once the sides are decorate you need to fold along the creased lines of the sides and stick the tab from one of the headboards to the side of the other side.
Add some strong dst to the edges of the mattress.
Very carefully line one edge of the mattress to the side. I watch from the bottom so that I can get the bottom of the tab lined perfectly.