I am happy to share my product design experiences with you here. They may give you some inspiration on how to apply the products within your activities.
I like to use cardboard, clay, rubber bands, lego, magnets and other easy to obtain materials. You get to see this from time to time in the videos included in the articles. Especially when I need to convey my ideas to those who prepare and operate machinery for mass production, prototypes and drawings are necessary.