You can chat with another person by finding them somewhere in OpenText Social Workplace (for example, by opening their profile or selecting them from the list of a community's visitors), then choosing Chat from the menu.
People with whom you have chatted are listed in My Chats. You can open someone's entry in My Chats to resume the chat with that person. You'll see all older chat comments (the chat transcript) above the typing area.
If someone starts a chat with you, you'll see a red dot beside My Chats, and another one beside the person inside My Chats.
To remove the red dots from all comments in a chat, choose Mark As Read from the menu. You can also choose this at My Chats on your home page to remove red dots from comments in all chats.