You can think of a 'Flow' as a 'path' that your customers 'get sent down' based on number of visits and is a powerful way to segment your customers to provide a more personalized experience as well as boost reviews on different sites.
For example, you can send customers to your Google page on their first visit and then to Facebook on their second visit. On the customer's third visit, they would cycle back around to the 1st flow and so on.
You can add a new flow by going to the 'SMS Settings' tab
From there, just click "+Add New Flow" to add a new SMS Flow:
Please note that some industries have this section disabled due to toll-free messaging policies. If you would like to make a verbiage change request, you will need to reach out to your account manager.