This video was made by the German organization Serrox Technischer Handel, which sells plastics fabrication items. Unsurprisingly, it promotes many their specialised items, but I think the fundamental course of action—which has very much to endorse it in excess of the slab-joint approach—could probably be tailored to perform without them. https://www.611676.com/acrylic-tabletop-sign-holders/298.html