It is possible to sync your Shopify store to the Spreadconnect App.
You simply need to go to the dashboard of the Spreadconnect App in Shopify and click on "Go Straight To Spreadconnect"
Please note that it will only work if it is a unique email address, and not connected to more than one Shopify store.
If this button does not show for you, it means that at this point in time you are not eligible to use admin.spreadconnect.app, for example, because you have two stores registered with the same e-mail address.