I was wondering if an administrator could point me to a wiki on how to Private Message?

Not sure there is a wiki page on it. But if you want to message a particular user, you'd click on their username. This will take you to their profile. On the left side of the screen underneath their picture, you would want to click "Send PM".

Just be aware that some users don't have e-mail notification enabled, so may need to log in to the site to know that they have a message.

The other option is under the avatar for the person there is a little symbol that will take you directly to the PM function. There is another one that will take you to the profile where you can send a message as FTMax described. All the codes like bold and color work just the same as they do on the forum.