Can I like twin a data type with another datatype in my situation?

Hello, Does someone knows how to twin different data types? Exemple , Im trying to make a group chat, but when I send a message, it wont apply to my conversations data base even if I have a field for it. Im pretty sure I need the unique ID of my Database and put it in the conversation field of my Message Data , but how exactly?
Here somes visuals! :stuck_out_tongue:

Thank you!

Hey there @joeymoriss7,

Whenever you send a message, make a change to thing (conversation) I’m assuming you create a new message, so you’d need to create the message first, then do the make a change to conversation and modify field “list of messages” add Result of Step…

Does that make sense?