Ok, you need to restructure how you’re saving the messages a little. I’m going to assume that a chat is like a topic that contains a list of messages related to the topic.
So for each chat, you’d need a list of messages. The messages field should be a list that is type text. When the Send button is clicked, the action should actually be “Make a change to parent group (that is, the popup)'s chat” > field to change is Messages: add MultiLineInput’s value. So you’re adding a new text to the message list within the chat that this popup is displaying.
Currently, the way you have it set up is whenever Send is clicked, you’re creating an entire new chat, which is incorrect. You just want to create a new message within the chat.
Also, in order to display the message list, your repeating group (in the popup) data source should be Parent Group (the popup)'s messages (the text list field). That’s it. Each cell will then be each text in that list.
Does this help?
Gaby | Coaching Bubble