Thanks to the reminder from actionfence on the HeroQuestFans discord that the official link hasn't really been shared prominently so
here it is !
Yes a bit of a mystery... is it just meant as nostalgic swag or were they planning some digital (app or web-based) design kit, perhaps where you drag and drop the icon from the right onto the map on the left and it automatically re-sizes? (and auto-saves? where do you put quest notes? or do you just "print screen" as is?)
You could certainly print it in two sizes (or split it in half in a paint program then do this) to get the right sizes and cut out shapes... this is actually the slowest way to do it. I don't think any of us really took the time to do it that way. Even the developers in the design drafts for EQP/BQP just took a blank map and free-hand drew the icons (or wrote in text labels, at best using a highlighter). The original actual Adventure Design Kit used a peel off sticker sheet of pre-cut icon images (with many copies of each icon) for you to use on five blank sheets (complete with space in the "quest book" for notes to hand write or type and paste the paper to the sheet too I suppose).