How to Start a Conversation (PM)
Near the upper right-hand corner, click on your avatar to open the drop-down menu and select Conversations from the navigation menu.
Once in your Conversations, click on the button at the top right, which says, Start conversation.
Next, type in the Recipients (Members' name).
Add a title.
Compose your message.
At the bottom, you also have the choice of allowing the recipient to invite other members to the conversation or to lock the conversation, not allowing anyone to respond to your message.
You can then send your message by clicking the Start conversation button or click Preview to see what it will look like to the recipient.