In the black menu bar across the top of the page, see the "My Messages" choice, sixth from left - hover your cursor over it and select "Read your messages". This brings up your incoming messages.
On the left side of that page, there's a column whose top row is labeled "Messages"; below that there's three choices: "New Message", "Inbox", and "Sent Items". This third one is your "out box", select "Sent Items" to see your outgoing messages.
That's how it works on my computer screen, anyway...