1. Go to Chats by clicking on the icon on the top navigation bar (top right of your screen)

2. Once you are on the chats view, click the "+" icon

3. Select the participant(s) you would like to chat with

4. Click Done

To find the "+" icon, see the image below:

To see where to select participants, see the image below:

To find the "Done" button to finally start the chat, see the image below: