Look to the upper right hand corner of your screen or monitor. You should see your own avatar, an envelope icon, and a flag icon. Click on the envelope icon and it will launch the "Conversation" user panel where you can send a PM to another member or see replies to previous PMs. Clicking on your own avatar will allow a member to access all of their personal account settings, and is a one-stop location for a vast number of other account related options. The flag icon is where members receive notifications to threads they're watching, or other system generated notifications based on the content a member previously participated in.