I have tried putting this together but it does not seem to make sense. Why is it asking me for a ‘subscriber list’ when there is no subscriber?? What am I missing? The customer registers to receive email updates. I am confused what to do here and I cannot find any tutorials..
Can I hear from some of the smarty pants who understand what am I asking please 
My store is with Shopify.
Sarah
Welcome to the community
Do you mean the ‘List to Submit’ setting (below) for the button click action on your pop-up?
This defines the list to which email submissions on your form will be pushed. You’ll need to create a list first for it to appear in the drop-down.
Then you create a flow that triggers when new contacts are added to that list. They will then receive your flow emails.
Does that answer your question? If so, I’m a smarty pants. If not… 
Regards
Andy
Hi there
To build off out what
Here are some helpful resources to help you learn more about everything possible in Klaviyo! Our Community allows you to learn from your peers who are experts in the industry, while our Academy has great courses and live trainings as well!
Hope this helps!
-Taylor
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