How do I connect with a Shopify account?

You should first go to the StockTrim listing in the Shopify app store and click "Install" https://apps.shopify.com/stocktrim

Shopify connected accounts must be created using your Shopify login - so if you have already created a separate StockTrim account you'll need to log out and connect via Shopify using your Shopify Store Name as above. Then you login normally from the main StockTrim login page and click "Sign in with Shopify".