Hi Phil
If you want to reply to a private message just type .r then a space then your message. eg:
.r Hi Phil, I can reply to your private maessages now.
If you want to send a private message to someone then type .m then a space then the callsign then a space then the message. eg:
.m ehm1703 Hi Phil, I can send you a private message now.
If you want to open up a seperate chat window to someone, type .chat then a space then the callsign and voila, a chat box appears. eg:
.chat ehm1703
If you want to add multiple pilots to your chat box, type in the chat window itself +callsign. eg:
+ehm948
Hope that helps,