The OP needs to know to click on the link named "User CP" and then in the User Control Panel to click on "Edit Ignore List" and then add the soon-to-be-ignored-troll's name to the "Add a Member to Your List. . . " box and click Okay. BTW, my ignore list is up to 274.
Unfortunately, for the ignore list to be really effective, the ignored member's remarks should also be hidden, especially when they're quoted during an admonition by a Moderator to "Don't feed the Trolls."