how can you get to forbidden city from tiananmen?

hi! will be coming from my hotel in hepingmen. with the help of google maps, i can take subway to qianmen and exit through A or B. Walk towards Chairman Mao's Mausoleum. Then walk to Tiananmen. But then I get lost on how to go to Forbidden Meridian Gate. Can I just walk to it or what would be the best way?