Export a CSV from your Shopify products view (not the inventory view). Make sure to include all products and use plain formatting.
If someone other than me somehow finds this page, welcome! You should probably know that all of my products have their type in the name (e.g. "Fuck Capitalism - Sticker"). The script does not rely on those product type strings to sort — it actually looks at the Custom Product Type property (sorry if you're using standard product types) — but it will attempt to strip out that part of the title, and if you have " - " in your product name it may mess up the displayed titles. Also, there is slightly different formatting for products with a type of "Shirts" (because they have sizes).