In the first canvas, the design will cut the front and the back of the design.

Process this side first, confirming your parameters. 

The bottom and sides are processed on the second canvas

If you use larger sheets than I did, you might be able to fit these pieces on a single canvas

I start with the back piece and glue in the bottom piece

I then glue in the sides, and I finish by gluing the front on last. 

I usually clamp the pieces until the wood glue dries. This is helpful if the wood has any slight warp to it. 

I've included pictures above to show the assembly order that works best.