To create a new chat click on the new chat icon located at the bottom of the page:
Firstly, type in the preferred Chat Name. Secondly, to add someone you will need to know their names and they need to be part of your project. If you want to make a chat with everyone in your project, type ALL into the "Add Chat Participants", otherwise you will need to add chat Members individually.
After that simply click on "Create" button.