Adding additional gluing surface to the frame edge for maximum adhesion of strip to frame is necessary for a strong structure.
The basic structure of hollow wood boards is called semi monocoque, and is the same type of structure used in aircraft construction.
Frame edge (supplemental) gluing strips can be added at different points in the process. In this photo you can see the added glue strips have been partially added to the frame.
Each cross frame and the full length of the spar should have small strips glued to the edge of the frame.
After some of the deck strips have been milled and the first strips for the deck have been laid out and cut to rough lengths, you will have some scrap pieces of stripping left over that can be used for some of the supplemental gluing strips.
You can add the supplemental gluing strips before you assemble the framework but this approach won’t allow for the use of “scrap” strip material and will consume more material.
Supplemental gluing strips can be cut “full shape” but consumes a great deal of material.
There are many ways to learn to safely use the tools and execute the processes necessary to build your hollow board. But the bottom line is this: Tools and the dust they create are dangerous. If you are a novice woodworker, educate yourself about tool safety and proper shop practices. Power tools are very unforgiving and trouble can happen quickly if you are not prepared and diligent in your approach to how you use these tools. Regarding the health consequences of breathing wood dust, take this issue seriously. Use good respirators with fresh, clean filters when cutting or sanding wood. This is also true for applying and sanding epoxy and other finish products. Uncured epoxy is toxic. Most of the ultra violet inhibiting finishes that go over the epoxy for the final finish are also toxic. Use the tools and materials at your own risk. Educate yourself and work smart and safe!