You can access your IM feature on the main page of the Forum, at the bottom in the "Info Center" block, by clicking on the number next to "Your Instant Messages"

Beyond the basic usage information found in the Site Help section, here are a few things you need to do if you use this feature:

1/ Inbox / Outbox maintenance — be sure to delete old messages from both your Inbox (the default window that comes up when you enter the IM section) and the Outbox. To reach your Outbox, click on the "Outbox" button at the top of the IM message window.

2/ Preferences - you can choose to ignore IMs from individual forum members by clicking on "Preferences" once you are at the Instant Message window, and then entering that person's username in the window. Be sure to hit "Save Preferences" or your changes will not be applied.

3/ Please do not post "Check your IM" threads in the forum to get someone's attention. They will be deleted. Either the person is paying attention or they're not.