By the time Dennis Marx drove onto the Forsyth County Courthouse plaza June 6 and started a gunbattle with sheriff’s deputies, he had already shot himself in the leg, according to information authorities released Tuesday. Sheriff’s office representatives included those details and others — including that some deputies had trained for just such an attack the day before — in a presentation at the morning meeting of the Lanier Forsyth Rotary Club. The officials laid out a timeline of the events, as well as previous interactions the sheriff’s office had with Marx, who was scheduled to appear in court that morning to enter a guilty plea on drug and weapon charges.