Users can start the direct messaging straight from the users list. Just look up the desired person and click the chat icon.

A chat window will pop-up in the bottom of the screen that allows for easy and instant messaging. 

Resume chats with users

From the user panel the new tile "My Chats" will bring you to the list with chats from the past. The most recent chat is in top and only the latest chat message from that user will be shown. Click the chat icon next to that user to resume that chat.