Once you've done the really hard part - selecting who you want to contact - actually getting in touch with them is easy. There are two methods to contact the other member:

While viewing their profile choose "Send Message" (first selection)
To write a message manually, choose "My Mailbox" and then "New Message"
You can then fill out that form with the username of the individual you want to contact.

Send them a message and/or add them as a friend.  Good Luck with your match!