There are a couple of options when it comes to chatting with your friends. You can either send a direct message to a friend or create a group chat with multiple friends. In order to send messages, you must have become friends first; you can find out how to add friends here.
To create a message:
- Navigate to the chats tab by tapping the 'Message' icon in the top right corner of any page.
- Tap on the 'Compose' icon in the top right corner.
- Tap on the friend you want to DM, or, if you want to create a group chat, tap on 'Create a new group'
You can learn more about how group chats work here