Hey @Niva Rubasha 

Welcome to the community!

Can you share a little more info on what you are looking to do and what you have already setup? Is your signup campaign and email that you are sending to your customers with an option to signup in the email, or are you using a signup form to collect subscriptions and you want to connect it to a flow? With the flow, what did you set as the trigger for the flow? 

With more info on how you are collecting the subscribers and how you have the flow currently setup we can help you connect the dots!