Please purchase a custom Product Template service and then send your specs. I think actually you already sent your specs, but you purcahsed a Developer License, which does not include free template services.
With a developer license you can use the blank square template (template ID 1) as a dummy template to test integration with in the mean time. You can also use this product ID with a plugin called TM Extra Product Options for WooCommerce by Theme Complete, to allow entering of any dimensions to create any size rectangular template by adding fields for “height” and “width”, but that won’t apply product graphics or custom masks to the template, that’s what we have to do by hand for you with our template service ($99 ea per side).
You can find the links to purchase new template services on your user dashboard where it says “Purchase Product Templates” here: