Let's say you want to connect 2 Shopify stores, named Store A and Store B to the same Sumtracker account.
To do so, please install the app on Store A first. When you install the app for the first time, you will sign up on Sumtracker and your account will be created.
To connect the Store B, you need to follow these steps -
Step 1 - Open the Shopify App page again and click on Add app
Step 2 - Login into Store B's account
Step 3 - When redirected to the Sign Up Page, click on Sign In at the bottom of the form
Step 4 - Use your existing Sumtracker account to Sign In
When you sign in to your account, Store B will be connected.
The same process can be followed to connect more stores if needed.