The easiest way is to upload the zip you get off of BOOTH/wherever to WorkUpload or PixelDrain (or both, or GDrive or another site, etc... they're just the most popular two) and make a post under the Gifts section with the name of the item from the listing, plus any English translations/anything else important for others to know.
You can link to an image off the listing to show as a preview, then post links to both the original listing's site and wherever you've uploaded it
Past that, it's your choice on how you like to format your own posts 🙂