To connect your Shopify account, first tap on +Create shipment for pickup in the Shyp app and then tap or on Shopify Orders.
You'll be prompted to enter your shop name, then you'll enter your email address and password. This email address and password should match the ones associated with your Shopify account.
Once complete, you'll be able to import your shippable Shopify orders. You'll only have to connect your account once unless you specifically log out or if you change your Shopify email address and/or password.