Short answer: We don't! We leave the making of things to professional Print on Demand companies that know what they're doing. Main Quest Studios just provides the custom art and designs and tells the service what to print them on and to ship it directly to you!
What this means is that the items you buy from this store don't exist as such until you order them! Only when you place that order do you set in motion the crafting of a custom product that ends up on your doorstep. It's even more evident with the 3D printed jewelry, because those items exist only as whatever feed stock the 3D printer consumes. It's imagination made real!
It also means that this is the only place you can get these items! You can't get them anywhere else!