Put your design on the canvas. Make it to fit your needs. I used the flex part of the File then stretched it to make the size I wanted. I then subtracted the nibs off the top and bottom so I could design a different lid. 

I copied and pasted the flex part then resized it to make what I needed for the lid.

I created circles the diameter that I needed and the rings to hold everything in place.

If your wood is different thickness than 2.8mm you may need to resize the inner circles! 

Lay out the parts for assembly. 

Glue the bottom outer ring to the bottom.  Next curve the flex around and glue the ends of it together. Insert the flex inside the outer ring. Now take the inside bottom part and put some glue on one side and push that side down inside the flex until it comes in contact with the bottom. 

Repeat for the lid.