Could someone tell me how is blue card working.

I get the idea that reports post to a moderator.
But when I log in moderator account there is no alert, no PM or anything about reporting post.
Then, how does moderator knows to check that post?

When a blue card is issued, an e-mail is dispatched to the moderators/administrators of that particular forum on your board.  The e-mail contains a link to the questionable content.

Thanks...again...for your answer