Facebook MarketPlace Message box

I am going to integrate a Facebook MarketPlace message box to my Laravel project. It is similar to the message box on Facebook or Facebook Marketplace. The only difference is for multi-users. In this project, I manage multi facebook users. So in the left section, display the users who are managed in this project. In the second section, display the users by the user in the left section. It means when you click the user in the left section, display the users who send a message to that user. The third section displays the messages. The fourths section displays the selling items. (it is not important) you can see the attached file. The design is not important.